Dan Drezner reviews the records of second-term Presidents to show that re-election doesn’t normally mean a more ideological second term:

What’s striking, however, is that recent second-termers have not reverted to their ideological bliss point — if anything it’s been the reverse. Part of this was circumstances. Reagan had, in Gorbachev, a real negotiating partner. Bush had to be more circumspect on Iran and North Korea after the cost of Iraq and Afghanistan. All three presidents had less favorable legislatures in their second term than their first.

What gives? I’d argue that precisely because presidents have fewer foreign policy constraints than domestic ones, they feel free to pursue their preferred set of policies from day one. Reality, however, quickly determines which ideas are working and which do not have any staying power. Over time, therefore, presidents change tack until they hit on a more successful formula. This usually means overcoming one’s personal ideology and embracing new ideas.

That makes sense, but what Drezner doesn’t discuss enough here is the extent to which second-term administrations really are freed from the constraints imposed by their own party bases. Granting for the sake of argument that the second Reagan and Bush terms were more “liberal” than their first (a very debatable proposition in Bush’s case), the reason for that is obvious enough: they no longer had to appeal to their core constituencies, and they were free to ignore them even more than they had before because they no longer needed them to win an election. Many movement conservatives found the second Reagan and Bush terms to be very disappointing for just this reason.

If not for presidential term limits, a second-term administration might very well become more ideologically ambitious. Woodrow Wilson’s second term stands out as a calamitous example of what could happen under the pre-22nd Amendment system. Since modern second-term presidents don’t have to keep their party bases particularly motivated and happy, they will usually look for something that will give them a legacy regardless of the backlash from the party base. For Reagan, that meant arms control in the context of reduced tensions with the USSR, and for Bush that meant trying to force through extremely unpopular immigration legislation. Partly because Bush was exceptionally unpopular (thanks to policy blunders that began in his first term, namely the Iraq war) and partly because the legislation in question was also unusually unpopular, Bush’s effort to secure a legacy failed. If we wanted to figure out what a re-elected Obama might do, we would need to identify something that prevailing wisdom in Washington insists is extremely important but which would infuriate and alienate progressives. In other words, it would probably be almost exactly the opposite of what people warning about an “unleashed” Obama expect. Offhand, the only thing that comes to mind that fits that description is overhauling Medicare.