Who should have easily won but ended up blowing it?

[KYRockefeller]

Dukakis would be a good pick for this as he just imploded after the spring in 1988.

Of the major choices, though, I'd pick Gore because he had more advantages than the other candidates.  Clinton was popular despite the Lewinsky scandal, economy hadn't quite entered the decline it would have throughout much of the 2000s (although the soft spots were starting to get exposed), and America wasn't under threat from a foreign menace.  Gore had a bad first debate from a perception standpoint, he didn't enlist Clinton's support in places like Tennessee or Arkansas, and lost.  The Liebermann pick probably hurt more than it helped too.

I'll always say Kerry would've won if he picked Dick Gephardt at the nominee.  I think that shifts enough labor votes in Ohio.

I really wanted Romney to win.  Biggest electoral disappointment of my lifetime because I think he would've been a good president.  However, the campaign didn't make a good VP pick, didn't keep the momentum going from a good first debate, and it let the Obama campaign define him as an out of touch plutocrat - which the 47% comment didn't help (an image that the Netflix doc on Romney shifted some views about him, though).  Also, the GOP base was never fired up about Romney and they had a rotating set of challengers before finally caving in and nominating him (Bachmann, Herman Cain's 9-9-9 plan, Newt Gingrich, and then Rick Santorum).  Romney did very little to solidify that part of the GOP coalition and that didn't do anything for his election efforts.

[KYRockefeller]

I often wonder how Perot could've done if he hadn't dropped out.  Still hard to fathom seeing him win but if he peels off even more support than the 18% or so that he got it would've been interesting to say the least.  House may have had to determine the outcome.