The political prognostication website 538.com explains that Obama’s supporters are more enthusiastic than McCains and suggests that the solution for McCain might be to put Mike Huckabee on the ticket to rev up evangelicals.

“It’s certainly the simplest and most direct way for McCain to lock down the support and enthusiasm of that desperately-needed evangelical organizing engine.”

Meanwhile, I’ve heard Democrats gleefully hoping (not praying) for a Huckabee selection because they think he’d be easy to caricature as a right wing yahoo.
Those who think Huckabee would help the ticket and those who think he would hurt both seem to be misunderstanding Huckabee’s strengths and weaknesses.
Frirst, let’s remember that Huckabee was NOT embraced by the evangelical establishment until late in the game because they viewed him as too liberal on too many things (mostly spending and crime). Rush Limbaugh didn’t like him, nor did The Wall Street Journal types, nor did many other evangelical leaders. But he was pretty popular with rank and file evangelicals.
Huckabee is a transitional figure in the evangelical world, and possibly a transformational one. As a strong pro-life politician and former Baptist preacher, he is a familiar and not-loathed figure among the evangelical old guard. Beyond that, his emphasis on Christianity as an uplifting rather than judgmental faith taps into the zeitgeist of the New Envagelicals. Younger evangelicals in particular have become convinced that leading a Bible-based, Christ-centered life might involve helping the poor and the environment, in addition to battling abortion. In tone and substance, Huckabee fits these evangelicals better than any Religious Right leader ever has.

In other words, he may not appeal to James Dobson but he may appeal to rank and file evangelicals, and maybe even Obamagelicals.
My big question is this: the evangelical hierarchy may not control all the votes (as we saw in the primaries) but they do have a disproportionate impact on the evangelical volunteer apparatus. So would Huckabee be able to translate his popularity with ordinary eangelicals into votes for McCain if the evangelical leadership a) hates McCain and b) only sort of kind of likes Huckabee?
Full disclosure: Huckabee has signed on as a commentator with Fox News, which is owned by News Corp, which also owns Beliefnet.