As I've noted earlier, 2008's may be the most heavily analogized election in American history. Barack Obama has been likened, often quite convincingly, to leaders ranging from Abraham Lincoln to Jimmy Carter. John McCain--the American Disraeli to admirers, the second Bob Dole to critics--isn't far behind.

Sarah Palin, though, seems to conjure up just one historical parallel: Dan Quayle, the dubiously qualified, polarizing newcomer who graced the GOP ticket two decades ago. Obama fans tend to see Quayle's deer-in-the-headlights look when they see Palin; the best many Republicans can do is note that Quayle's candidacy didn't prevent his ticket from winning a landslide victory.

Now, a month into her candidacy, the battle is joined: In a speech at the Harry Truman Library today, McCain sang the praises of the little-known, oft-derided Missouri pol thrust into the presidency by the 1945 death of Franklin Roosevelt. The comparison, of course, is a little scary--evocations of successful veeps tend to involve evocations of the presidential deaths that elevated the veep to greatness, as FDR's did less than three months after Truman's election. But the comparison is also analogistic gold: Truman is a bipartisan presidential hero, the patron political saint of underestimated middle-Americans and unpopular presidents. McCain's speech didn't even mention Palin. Given the stellar popular-culture image of the plainspoken Harry S., it didn't have to.

So long as we're going back in history for both positive and negative comparisons, let me nominate my own scary vice-presidential analogue for the Alaska governor: John Tyler, the nation's 10th vice president. Running alongside an elderly war-hero candidate, the Virginian was nominated as a balancing gesture, to soothe the sectional divisions within his Whig Party. It worked, as Tyler helped reassure both slaveholding Southerners and stalwarts of party hero Henry Clay about the man at the top of the 1840 ticket, William Henry Harrison.

Of course, the dangers of nominating an extremist on the day's big issues soon became clear: Harrison, the great hero of the Battle of Tippecanoe, went on to die a month after being sworn in, making Tyler the first veep to succeed following a presidential death. True to his political roots, Tyler took a series of strongly pro-Southern stands that fractured the coalition that won the 1840 election. He didn't serve a second term and wound up dying in 1862 in Richmond, where he lived as a loyal citizen of the Confederate States of America.

--Michael Schaffer