John Podhoretz writes:
In one respect, Paul deserves his success. He is a far more articulate and coherent critic of administration policy in Iraq than any candidate on the Democratic side, speaking as he does the frank and plain language of the isolationist. “The fundamental question remains,” he said in 2004, “Why should young Americans be hurt or killed to liberate foreign nations? I have never heard a convincing answer to this question.”
What distinguishes Paul from the anti-war gadfly Dennis Kucinich in the Democratic Party is that Kucinich speaks alternately the language of the brainless pacifist — he would form a Department of Peace to replace the Pentagon — and the language of the far from brainless New Left, according to which the sins of the United States are sufficiently grave to deny it any kind of moral legitimacy abroad. Paul’s isolationism is rooted in the age-old American fear that we will be morally compromised by the sins of other nations who do not breathe the same sweet air of American exceptionalism.
I basically agree, though I think the last line abstracts a bit from first-order political concerns in order to be dismissive. (One could just as easily describe Paul's isolationism as rooted in "the age-old American fear" of having your kids killed and your tax dollars squandered on a fruitless overseas crusade - which is likewise compatible with traditional American patriotism in a way that New Lefty Amerika-bashing isn't.)
On the third-party question, meanwhile, JPod suggests that despite "Paul’s nominal standing as a Republican," he would probably "draw more from disaffected Democrats, as liberal Republican John Anderson’s 1980 third-party candidacy pulled voters away from Jimmy Carter and not from Ronald Reagan." This runs counter to Steven Stark's argument, over at RCP, that any third-party run helps the Democrats, because historically, third-party candidates always "damage the candidate of the incumbent party." (I think I'm with JPod if the Democratic nominee is Hillary Clinton; I'm with Stark if it's Obama or Edwards.)
Elsewhere, Michael Crowley writes, "can you imagine if Paul were a younger and more charismatic figure?" I've had this thought myself: What if Ralph Nader's ideas had been represented by someone who looked and sounded like Ronald Reagan? What if Ross Perot had been blessed with Bill Clinton's charm? What if the Buchananite revolt hadn't been led by, well, Pat Buchanan? But in a sense, to ask the question is to answer it: If you're young and charismatic and interested in politics, the rewards to staying within the mainstream political consensus are so high, and so readily apparent, as to be near-irresistible. If Ron Paul looked and sounded like Bill Clinton, he probably never would have become a constitutionalist in the first place. (Though of course Reagan himself was arguably an exception to this pattern - a rising star who embraced "extremism" when every sensible person was rushing away from it - and look how that worked out for him.)
In the particular case of Paul, one might also venture that being a crusty old coot is actually part of his appeal, rather than a liability. (At the very least, it makes that Weyrich endorsement seem downright perverse: If there were ever a potential standard-bearer for streetcars and male hats, surely it's the candidate who doesn't know Tom Cruise from Tom Swift.)
Update: Matt makes a similar point to the above:
The difficulty is that in a country as big as the United States, it's easy for a set of views to simultaneously be very unpopular and also be supported by millions of people, but out of those millions of people the folks who decide to enter electoral politics in order to take on a principled, "no compromise with the electorate" approach are going to be the eccentrics. More normal, well-adjusted people with extremist views are going to prefer to do something less frustrated and isolating with their lives.
As a result, views like Kucinich's social democracy and Paul's libertarianism wind up represented by eccentric politicians, which winds up making their views seem weirder than they deserve to be.