For four decades, American public opinion on the issue of abortion has been largely unchanged. As the numbers from Gallup, the Pew Research Center and other polls show, roughly half of Americans have identified themselves as "pro-choice" even as consistent majorities support keeping abortion legal in all or many circumstances.

But now, a new survey conducted for Vox by the communications and strategy firm PerryUndem revealed that for Americans abortion is "not so black and white." Where past polls found a public bitterly divided over the legality of abortion, the Vox survey found nuanced views and surprising common ground. When questions moved "beyond legality and into [the] reality" of the abortion experience for American women, a much different picture emerged.
Nearly four-in-ten respondents said they were "neither" (21 percent) or "both" pro-choice and pro-life. Just changing the wording from "abortion should be legal in almost all cases" to "women should have a legal right to safe and accessible abortion in almost all cases" produced a 9 point jump in approval. Even more important, when the 1,067 adults were asked about what a woman's actual abortion experience should be like using terms like "comfortable," "supportive," "without pressure," "non-judgmental," "affordable," "informed by medically-accurate information," or "without added burdens," the transformation was even more dramatic. As ThinkProgress summed it up:

A large majority of respondents -- at least 69 percent -- said "yes" for each of those descriptors, suggesting there's consensus about how Americans want women to be treated after they choose to seek an abortion. This aspect of Undem's polling is "really groundbreaking," according to [Kate] Stewart [of Advocates for Youth].

But while PerryUndem further found that Americans were unfamiliar with just how common abortion is (1 in 3 women have terminated a pregnancy by age 45) and that support for women's reproductive rights was much higher among those who had talked to someone experiencing the procedure, in one area the survey shed little new light.
If support for women's safe and legal access to abortion is surprisingly broad, why are anti-abortion extremists enjoying even more surprising success at the ballot box?
In a nutshell, the answer is intensity. Anti-abortion voters simply care more about erasing women's reproductive rights than their supporters do about preserving them. And in some regions of the country and in off-year elections, that difference in motivation, commitment, activism and turnout makes all the difference.

The numbers tell the tale. By early February, the Kaiser Family Foundation reported, state lawmakers had already introduced over 100 pieces of legislation in 2015 to curb abortion access. And as Pew noted:

According to the Guttmacher Institute, a research group that supports abortion rights, 15 states enacted 26 new abortion restrictions in 2014, substantially fewer than the 22 states that enacted 70 restrictions the year before. Still, from 2011 to 2014, 231 abortion restrictions were enacted, while 189 were enacted during the previous decade (2001-2010).

As it turns out, that contradiction isn't much of a paradox after all. As a 2013 survey by the Pew Research Center revealed, views on abortion vary widely by religion and region of the country. For example, 75 percent of New Englanders believe abortion should be legal in all or most cases; only 20 percent are opposed. But in the South, opponents outnumber supporters by 52 to 40 percent. Still, with the passage of harsh anti-abortion laws in traditional (and trending) blue states including Ohio, Wisconsin, Pennsylvania, Florida and Virginia, geographic and religious disparities don't sufficiently explain the seeming momentum of the anti-abortion movement in recent years. To fully comprehend the changing landscape, you need to understand both voters' intensity and when they actually go to the ballot box

As it has since the mid-1990's, in 2013 a Washington Post/ABC News poll found a steady advantage for pro-choice supporters, "with 55 percent saying abortion should be legal in all or most cases, while 41 percent say it should be illegal in most or all cases." But that number obscures the huge gap in intensity between pro-choice and anti-abortion voters. A survey that same July by NBC News and the Wall Street Journal revealed that only 26 percent of respondents described abortion as a high or very high priority for Congress and state legislatures, with 72 percent brushing the issue off a medium or low priority. NBC pointed out the yawning chasm in intensity between the two sides:

There is a striking divide when it comes to intensity. Among those who believe abortion legislation should be a high priority for state and federal lawmakers, a combined 70 percent say abortion should be illegal in all or most cases.
And among those who think it should be a low priority, 65 percent say it should be legal either always or most of the time.

Making matters worse for pro-choice Democrats, an "age gap" in voter intensity works against them as well. As Pew explained in "5 Facts about Abortion":

Roughly six-in-ten Americans (62%) know that Roe v. Wade was a decision about abortion, but among adults under 30 years old, only 44% know. Younger adults also are less likely to view abortion as an important issue: 62% of Americans ages 18-29 say it is "not that important" compared with other issues, while 53% of adults overall say this.

In the midterm years of 2010 and 2014, those older, more conservative voters turned out in big numbers. The millennials? Not so much. Those results would have come as no surprise to Michelle Goldberg, who two years ago in "The GOP's Abortion Obsession" quantified the ferocity of social conservatives' anti-abortion views that make them such a force in off-year elections and Republican primaries:

According to a Washington Post/Kaiser Family Foundation poll taken last year, 63 percent of Republicans believe abortion should be illegal in all or most cases. Among those who identify with the Tea Party movement, the number is 88 percent. These are the party's activists, the people who turn out for crucial primary elections--and, in many cases, mount primary challenges of their own. Their will can't simply be ignored.

Can't be ignored, that is, during non-presidential election years.

As the numbers from the U.S. Census Bureau's Current Population Survey reveal, presidential election years produce a roughly 15 to 20 point increase in voter turnout compared to midterm Congressional elections.

In 2008 and 2012, Democrat Barack Obama benefitted from turnout of 63.6 and 61.8 percent, respectively. Those years included strong showings among younger, black and Hispanic voters. But Obama's coalition let him down in the 2010 midterms, when the 46.7 percent turnout was three points lower than four years earlier. In 2014, as we'll see below, voter turnout plummeted to its lowest level since 1942. As the Guardian summed up the 2012 Democratic debacle:

1. The 2008 electorate was 74% white, plus 13% black and 9% Latino. The 2010 numbers were 78, 10 and 8. So it was a considerably whiter electorate.
2. In 2008, 18-to-29-year-olds made up 18% and those 65-plus made up 16%. Young people actually outvoted old people. This year, the young cohort was down to 11%, and the seniors were up to a whopping 23% of the electorate. That's a 24-point flip.
3. The liberal-moderate-conservative numbers in 2008 were 22%, 44% and 34%. Those numbers for yesterday were 20%, 39% and 41%. A big conservative jump, but in all likelihood because liberals didn't vote in big numbers.

Larry Sabato and his University of Virginia co-authors summed up "the presidency's political price" for Barack Obama: Democrats lost 63 House seats, six Senators, 8 governorships and 10 state legislatures.
The much older electorate in 2010 didn't just defeat Democratic candidates like Ted Strickland in Ohio and Joe Sestak in Pennsylvania. Voters over 65 gave their votes to Republicans by a whopping 21 point margin (59 to 38 percent). And, Pew reported, the elderly are much less pro-choice than the population as a whole:

Among adults under age 30, 57% say abortion should be legal in all or most cases, the same as among adults in their 30s and 40s (57%) and similar to those in their 50s and early 60s (55%).
Americans 65 and older are somewhat less supportive of legal abortion. Equal portions say abortion should be legal in all or most cases (45%) and illegal in all or most cases (45%).

That pattern certainly held in Florida, where the GOP's Rick Scott eked out a one-point win in 2010 despite that fact that Obama defeated both John McCain and Mitt Romney there. As the Sun Sentinel explained the turnabout:

The Republican tsunami in Tuesday's election was intensified by a low turnout among the Democratic strongholds of South Florida.
It was the worst turnout for a gubernatorial election in at least 12 years in both Broward and Palm Beach counties. Only one other county in the state posted a worse turnout than Broward, where just under 40 percent of registered voters went to the polls. Turnout in Palm Beach was 46 percent, but that's still lower than the rest of Florida.

In traditionally Democratic Pennsylvania, gerrymandering and abysmal turnout in 2010 gave Republicans control of the governor's mansion and the legislature. Turnout was "in the 46 to 47 percent range," compared to the presidential election of 2008, which brought 70 percent of registered voters to the polls.

That midterm intensity disadvantage for Democrats and abortion rights supporters has been even more pronounced in recent off-year elections. In New Jersey in 2009, Republican Chris Christie defeated unpopular incumbent Democratic Governor Jon Corzine in an election in which "voter turnout was a record low for a New Jersey governor's race." That same November, Tea Party radical Bob McDonnell defeated Democrat Creigh Deeds in Virginia. As the Washington Post reported:

With turnout in a governor's race slumping below 40 percent for the first time in at least 40 years, Deeds fell well short of the margins Obama, Kaine and Warner amassed among black voters, young people and Northern Virginians.

In both 2008 and 2012, three million people cast ballots in blue state Wisconsin as turnout reached 69.2 and 70.1 percent, respectively. Barack Obama carried the state each time. But in 2010, turnout dropped back to 49.7 percent and 2.17 million votes, enabling Republican anti-abortion hardliner Scott Walker to become governor. Walker survived his controversial recall election in June 2012, again in large part because Democrats did not get their voters to the polls:

While there was a heavy turnout for a special election, the final total of just over 2.5 million votes fell well short of the nearly 3 million votes cast in the 2008 presidential election. And Republicans appear to have done a better job of getting their voters to the polls. Turnout for the recall election was 91 percent of 2008 turnout in heavily Republican Waukesha County, the largest GOP county in the state, but only 83 percent of 2008 turnout in Milwaukee County, the largest Democratic county in the state.

The same pattern was evident in the exit poll results. In 2012, the Walker recall electorate was noticeably older, whiter, more conservative and more Republican than the 2008 electorate.
But for Democrats and their pro-choice allies, 2014 represented a new low. Turnout nose-dived to around 37 percent. It was bad enough, as Vox illustrated with the charts above, that the electorate is whiter and older in non-presidential years. The 2014 midterm slaughter came in a year when the GOP had a much larger favorability gap and when Americans agreed with Democrats on almost every issue.

As Zachary Goldfarb explained after the Democrats' November 2014 beat-down, "Americans will vote for Republicans even though they disagree with them on everything":

Voters are a confused lot. Yes, they have fallen out with Obama, but on the biggest issues facing Congress, they still agree with Democrats on ... almost everything. That includes issues like raising the minimum wage, making the rich pay more in taxes, letting illegal immigrants stay in the United States, taking action to stem global warming, legalizing same sex marriage and fixing the Affordable Care Act rather than repealing it.

When it comes to abortion, voters may be a confused lot. Polls show that some Americans don't realize that Roe v. Wade is about abortion or what it says. Seventy-three percent in the PerryUndem survey said they were surprised that one in three American women had had an abortion. And as Tresa Undem pointed out, when her survey respondents saw a chart of new abortion restrictions being implemented in the 50 states, they weren't just shocked:

Undem said that, as a researcher, it's been "astounding" to see the strong reactions this graph provokes. "When you get in a focus group with people and you show them the entirely of the restrictions and exactly what's going on, there is total outrage -- it's unlike anything I've ever seen in fifteen years of doing public opinion research," she said...
"One thing that really surprised me is that what comes of out of this outrage is a real desire to act. We often do research to change behavior, and I've never seen anything like this that has so much potential," Undem said. "Unprompted, these people will say, 'How do I have a voice on this? Who do I call?' It's really powerful."

Lamentably for abortion rights activists, so far that potentially outraged majority has been a largely silent one. Right now, their opponents have cornered the market on outrage. They are, as Barack Obama might have put it, "fired up and ready to go." When turnout is low and the presidency isn't on the line, those anti-abortion voters still go to the polls. And that's why--and when--anti-abortion intensity trumps Americans' pro-choice propensity.