More likely than not, then, this decision will mean the end of Paul's career as an elected official, as he is a long shot to win the White House in 2012 despite enjoying probably the most enthusiastic supporters of any candidate in the race and performing solidly in national polls. Paul placed second in a recent nationwide NBC/Wall Street Journal poll, collecting 11 percent (tied with Rep. Michele Bachmann) behind Mitt Romney's 43 percent. His best showings in 2008 came in North Dakota and Maine, where he finished second.

Paul's 2008 campaign changed things. It brought libertarians out of the woodwork, revolutionized online fundraising for conservatives by breaking single-day records and inventing the "money bomb," helped give rise to the tea party movement, and made it okay for Republicans to oppose foreign wars. It gave libertarians power within the Republican coalition, dragging the GOP's center of gravity far enough toward fiscal austerity and social agnosticism that Republican politics became the main outlet for libertarians, who have always had to choose between the GOP and the Libertarian Party.

Without Ron Paul's 2008 debate performances, we might not see Mitt Romney campaigning against the war in Afghanistan on stage today. Without his public campaign against the federal reserve and government interference in people's lives, the tea party's small-government flavor wouldn't be the same.

In his November 2010 magazine piece about Ron Paul as "The Tea Party's Brain," The Atlantic's Joshua Green explained how the housing bubble and the recession helped make Paul into the star he is:

THEN EVERYTHING CHANGED. The housing bubble burst, banks stopped lending, and the Federal Reserve became an object of contempt. It was the world Ron Paul had prophesied, and he had a seductive story to tell about why it had happened--the Austrian story. The Federal Reserve, in its hubris, had thought it could goose the economy and mitigate the effects of a post-9/11 recession by holding interest rates low, he explained. But tampering with money had sown disaster, just as Mises had warned. Easy credit had fueled massive amounts of what the Austrians called "malinvestment"--badly allocated investments, in this case in the overproduction of houses and automobiles. Only no one recognized this, because the true value of money had been distorted. Now the reckoning had arrived. For his devotion to Austrian economics, Paul was always seen as slightly aberrant, in the same way that he might have been if he were, say, a practicing Druid. The Austrian school had peaked in the early 20th century but had fallen away after the Great Depression, which it claimed was caused by an expansion of the money supply and could be met only with chastened submission as the market corrected itself. Herbert Hoover's Treasury secretary, Andrew Mellon, offered similar counsel, famously urging Hoover to "liquidate" and "purge the rottenness out of the system." But this failed to stop the catastrophe. Only when Roosevelt took the dollar off the gold standard and committed to deficit spending, and the Fed adopted consistently low interest rates, did the economy finally start to recover. This validated the argument of the Austrians' intellectual adversaries, economists like John Maynard Keynes, that rather than stand aside, governments should intervene to mitigate recessions.

Paul will take one more shot at the presidency, having already shifted the mainstream and accomplished some of his goals -- the creation of a movement and shifts in how the right looks at economics and government.

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