Obama needs to do one other thing, however, that will make his task much easier. He must champion reform of the Senate. The current combination of filibuster and hold rules limits effective legislative reform, and it makes it difficult for Obama to staff federal agencies -- like the new consumer protection agency and the Federal Reserve -- with experts who will promote his policies. It also prevents him from stocking the courts with new judges who agree with his constitutional values. As Reagan well understood, no transformation in political regimes is complete without a transformation of the executive branch, the independent administrative agencies, and the judiciary.
Democrats have little to gain from sticking with the existing Senate rules. If Mitt Romney wins and his party retakes the Senate, the Republicans will have few scruples about changing the rules of the game to promote their policies. McConnell has no intention of allowing current Majority Leader Harry Reid to do to him what he did to Harry Reid. Because some kind of Senate reform is inevitable, it is rational for the Democrats to benefit from it first, while they can.
Of course, if they retain control of the House in the 2012 election, Republicans have one last card to play: impeachment. Republicans have been trying their best to find a damaging scandal during Obama's first term, so far with little success. But the longer a presidency lasts, the greater the chances are that something will turn up, especially in a president's second term. And if a scandal takes off, Republicans can try to impeach Obama. Scandal and impeachment are serious dangers for preemptive presidents, whose legitimacy is usually already under siege. It is worth noting that of the three presidents who have either been impeached (Andrew Johnson, Clinton) or resigned under threat of impeachment (Nixon), all three were preemptive presidents (Johnson, a war Democrat, became president following Lincoln's assassination and quickly got caught up in a power struggle with a Republican Congress).
Finally, if Obama wants to make his influence lasting, he must work to create an economy prosperous enough to help ensure that a Democrat follows him in 2016. Preemptive presidents usually aren't succeeded by members of their own party, but reconstructive presidents often are. If another Democrat -- say, Hillary Clinton -- takes the oath of office in January 2017, that will be the strongest indication that, at least for the Democrats, it is morning in America. The Age of Reagan will be over, and the Age of Obama will have begun.