Last week, former New Mexico Governor Gary Johnson announced his plans to seek the GOP presidential nomination in 2012. His anti-entitlement, anti-tax orthodoxy notwithstanding, Johnson was something of a conservative iconoclast as governor of New Mexico; he opposed the wars in Afghanistan and Iraq, as well as the recent intervention in Libya. He supports marijuana decriminalization, and is a staunch opponent of the war on drugs. As a few others have noted, Johnson is a natural fit for libertarians on the right and left, and he holds appeal for liberals as well. In his blog post celebrating Johnson’s decision to run, The Spectator’s Alex Massie captures some of this enthusiasm:

If President Johnson were to end the Drug War and that were his sole achievement in office he’d have done more good than any President in 40 years. Not since Milton Friedman helped end the draft has there been a better cause. That alone demands one welcome Johnson’s decision, announced at some point today, to enter the race for the Republican party’s 2012 presidential nomination.

Now, here’s the problem: if Johnson is a serious candidate for president, then these views will become less significant as the primary season wears on. That is, for Johnson to find real success within the Republican primaries, he’ll have to raise money from GOP donors and satisfy the issue preferences of GOP elites, donors and primary voters. And to that end, he’ll have to repudiate positions—like marijuana decriminalization and marriage equality—that run counter to the views of most Republicans.

In other words, for Johnson to even have a shot at the nomination, and thus a shot at the presidency, he’ll have to become a run-of-the-mill Republican, and not the transformative figure his supporters hope for. Put another way, when it comes to winning a presidential primary, the actual views of a candidate—while not unimportant—are ultimately less significant than intra-party conflicts, elite pressures, fundraising and grassroots organizing.

Relatedly, this goes a long way toward explaining ongoing liberal disappointment with Barack Obama. It’s not that Obama entered office and immediately moved to “sell out” the Left, but that in running for president, Obama made a lot of promises to a lot of people within the Democratic Party, and he has to juggle those interests along with his own agenda. If an issue like Guantanamo falls by the wayside, it’s partially because the administration has limited energy and competing concerns. Unfortunately, this isn’t a very satisfying explanation.