Gun Control: McCain was once a vocal advocate for stricter gun-control laws. As Think Progress points out, he even appeared [6] in ads for the nonprofit Americans for Gun Safety urging states to close the gun-show loophole that lets people buy firearms without a background check. But McCain made a dramatic reversal this past spring. He introduced a bill that would force the District of Columbia to repeal its gun-registration laws and allow residents to transports firearms within the district.
Don't Ask, Don't Tell: Four years ago, former war hero McCain seemed willing to consider changing the military's ban on gay service members. "The day that the leadership of the military comes to me and says, ‘Senator, we ought to change the policy,' then I think we ought to consider seriously changing it," he said [7]. But in February 2010, when Defense Secretary Robert Gates and Joint Chiefs Chair Mike Mullen testified that they supported Obama's desire to repeal DADT, McCain rebuffed them. "At this moment of immense hardship for our armed services, we should not be seeking to overturn the 'don't ask, don't tell' policy," he said after the testimony.
Climate Change: Once a key supporter of cap-and-trade legislation—he co-sponsored a 2003 bill [8] and declared during his 2008 campaign that the country urgently needed to address global warming—McCain now calls it "cap-and-tax [9]," and has tried to claim that he never supported the policy to begin with.
McCain could soften his newfound positions prior to November. But since he’s safely ahead [10] of all of his Democratic challengers, there’s little incentive for him to change up now. Moreover, his flip-flopping mirrors his party’s rightward creep: For example, Sen. Lindsey Graham—whom many have compared to the old John McCain—has similarly abandoned efforts [11] to work with Democrats on climate change and immigration.
If the GOP expands its congressional ranks significantly this November, it could bring a degree of ideological diversity back into the party [12] if moderates like Mike Castle, Charlie Crist, and Mark Kirk are elected to the Senate. But given the beating he’s received from the conservative base since stepping into the national spotlight, it's unclear whether the old McCain will ever come back.