Among the supposed revelations in the new book by former Obama adviser David Axelrod is the claim that the 44th President was "bulls**ting" about his past opposition to marriage equality. While President Obama today claimed otherwise, his deference to political expediency was no mystery to his supporters. For them, his Hamlet act that his views were "evolving" was rightly received with eye-rolling and a shrug.
But complaining about Obama's failure to live up to his own high standards, the Washington Post's Aaron Blake declared, "This is why we're cynical." To put it bluntly, that is bulls**t. Obama's gambit had no impact on the 2008 election. If you want to see a history-changing act of political cynicism, you'll need to go back to Governor George W. Bush in the 2000 election. His stunning--and almost instantly reversed--call for limits on greenhouse gas emissions including carbon dioxide helped the Republican "out-Gore Gore" and end up in the White House.
In his speech in Saginaw, Michigan on September 29, 2000, Governor Bush tried to beef up his "compassionate conservative" credentials by outflanking Vice President Gore from the left:

"As we promote electricity and renewable energy, we will work to make our air cleaner. With the help of Congress, environmental groups and industry, we will require all power plants to meet clean air standards in order to reduce emissions of sulfur dioxide, nitrogen oxide, mercury and carbon dioxide within a reasonable period of time. And we will provide market-based incentives, such as emissions trading, to help industry achieve the required reductions."

As it turned out, Bush kept that promise only until he was safely ensconced in the Oval Office.
In March 2001, only 10 days after EPA administrator Christie Todd Whitman publicly pledged to fulfill Bush's campaign promise, the White House reversed course. Later that year, Whitman was rolled again over the issue of "new source review" for the nation's older power plants. The EPA's suggested rule changes were rejected by the administration, she said, because the White House "wanted something that would be more pro-industry." (Caught completely off-guard while in climate meetings in Europe, Whitman soon resigned.)
Just days before abandoning the Kyoto climate treaty altogether, President Bush jettisoned his campaign promise to "establish mandatory reduction targets for emissions of four main pollutants" including carbon dioxide. As the New York Times reported on March 13, 2001:

The president outlined his new view in a letter to four Republican senators, whose criticisms of Mr. Bush's initial plan had been among a torrent of protests by conservatives and industry leaders who warned that any effort to regulate carbon dioxide emissions could deal a severe blow to the energy industry and to the American economy.
As recently as 10 days ago, Christie Whitman, the new administrator of the Environmental Protection Agency, had described Mr. Bush's campaign promise as if it were already policy.

The imprint of Vice President Dick Cheney's office was clear in a White House memo which warned "any specific policy proposals or approaches aimed at addressing global warming must await further scientific inquiry." President Bush parroted that language in his March 2001 letter to the GOP Senators which reversed his plan to regulate CO2 emissions "given the incomplete state of scientific knowledge of the causes of, and solutions to, global climate change."
To provide a smoke-screen for its support of industry, the Bush administration continued to turn to its magical formula of "scientific uncertainty." Despite the overwhelming worldwide consensus on the urgency and man-made causes of global warming, President Bush in rejecting the Kyoto protocols in June 2001 declared:

"No one can say with any certainty what constitutes a dangerous level of warming, and therefore what level must be avoided.
The policy challenge is to act in a serious and sensible way, given the limits of our knowledge. While scientific uncertainties remain, we can begin now to address the factors that contribute to climate change."

Mercifully for the American people, in April 2007 the United States Supreme Court did what President Bush would not, ruling that carbon dioxide should be considered a pollutant under the Clean Air Act. As the Washington Post noted at the time:

As a result, the court said, the EPA had not only the power but the obligation to regulate the gas.

The occupant of the White House eventually came to the same conclusion. But his name was Barack Obama, not George W. Bush. Obama may have played it cute in fudging what he was against when it came to marriage equality. But Bush pretended he was a strong environmentalist, he was lying his way to the presidency.