My belief that John McCain is the lesser of the available evils in this election is largely based on the advantages of divided government. As I have explained in the past, divided government places important constraints on the growth of the state. Congress is more likely to increase federal regulation and spending if the president who gets to do the regulating and spending belongs to their own party. The president is less likely to veto or oppose congressional extensions of government power if those extensions are produced by his own partisan allies. Libertarians justly complain about the vast growth of government under George W. Bush; but that growth was largely a product of Republican united government from 2001 to 2006.
If Obama wins, he will have a strong Democratic majority in both houses of Congress to work with. This state of affairs is likely to lead to a significant expansion of government even in the best of times. However, now is clearly not the best of times. It is a time of economic crisis. And economic crises are also excellent opportunities to expand the powers of government - opportunities that politicians rarely let slip.
Obama's ideological orientation also plays a role in my thinking. While I believe that his foremost objective is to get elected and reelected, I think he's also an ideological big government liberal. His record in Congress and in Illinois reflect that. Obama might be willing to set aside ideology for the sake of political self-interest if the two conflict. But if he takes office at a time of crisis with large Democratic majorities in both houses of Congress, there won't be any such conflict between political self-interest and his big government instincts. The two will in fact be mutually reinforcing.
Once enacted, extensions of government power are very difficult to reverse, even long after the crisis that allegedly justified them has passed. For example, we are still saddled with the perverse system of farm subsidies and price cartels established by the Depression-era Agricultural Adjustment Act.
The combination of united government, economic crisis, and a president with big government instincts is likely to produce a major, permanent expansion of federal power.
Whatever his other flaws, McCain's election is likely to impede this process, at least to some extent. Moreover, although McCain has some statist tendencies of his own, he does have a pro-market side as well. He is pro-free trade, he was one of only a handful of GOP senators to vote against Bush's 2003 prescription drug plan (the biggest new government program since the 1960s), and he has called for a freeze on most domestic spending and for limits on the growth of entitlements. McCain also deserves a measure of libertarian credit for supporting expanded immigration in the face of opposition by many conservatives. As co-conspirator David Bernstein points out, McCain is also likely to appoint judges who are more sympathetic to libertarian positions than any we could hope for from Obama. On all of these issues except for immigration, Obama is far more statist than McCain. And there are few if any countervailing examples where Obama is more libertarian than his opponent (perhaps electronic surveillance is a rare exception, though Obama's position on that issue is muddled).
That is not to deny that McCain has many flaws from a libertarian point of view. Some of these, however, might be restrained by divided government. For example, like George Will, I worry about McCain's impulsive temperament. However, it will to some extent be offset by a strongly Democratic Congress. Left to his own devices, for example, McCain might be too eager to attack Iran in order to forestall their efforts to acquire nuclear weapons. But McCain is a smart enough politician to know that it is politically dangerous for a president to start a major conflict without strong congressional support. Thus, a President McCain will not attack Iran unless he gets backing from congressional Democrats. And, after the Iraq experience, the latter are unlikely to give it to him unless he presents an exceptionally strong case for action.
McCain still has numerous shortcomings. Just consider his positions on issues like campaign finance, national service, and the bailout, among many others. It's possible that I would prefer Obama to him if the latter came to power during a time of optimism and was constrained by a hostile Republican Congress, as Bill Clinton was. I might also prefer a Democratic victory if that party were likely to follow the centrist, market-friendly policies that characterized Clinton's last six years in office. In the current environment, however, that is highly unlikely. McCain is seriously flawed; Obama and a united Democratic government are likely to be significantly worse.
UPDATE: Readers may be interested to know that my support for divided government is not of recent vintage, and cuts both ways. Back in 2006, I argued in this series of posts that it would be good for the country if the Democrats retook control of the House of Representatives.