IOWA…. Democrats everywhere love poll porn right about now, but this is especially notable under the circumstances.

Democratic presidential nominee Barack Obama has strengthened his advantage in The Des Moines Register’s Iowa Poll, establishing a commanding lead over Republican John McCain heading into Tuesday’s election.

Obama has widened what was a solid lead in the Midwestern swing state, and has strengthened his position on key leadership traits since the Register’s September poll. Meanwhile, support for McCain and perceptions of his abilities have slipped despite several campaign appearances in the state this fall.

Obama, an Illinois senator, was the choice of 54 percent of likely voters, while McCain, an Arizona senator, was the choice of 37 percent. […]

Obama’s 17-point lead was up from 12 percentage points in the Register’s previous poll, taken Sept. 8-10. Meanwhile, his supporters’ confidence in him also improved, while confidence in McCain by his supporters slipped, according to the poll.

I’d note, for those who’ve forgotten, that the Register’s Iowa Poll is arguably the gold standard for polling in the state, having gotten the results of the January caucuses exactly right.

On Friday night, of course, the McCain campaign released a detailed memo about the state of the race. “Our numbers in Iowa have seen a tremendous surge in the past 10 days,” the McCain campaign insisted. “We took Obama’s lead from the double digits to a very close race…. Like many other Midwestern states, Iowa is moving swiftly into McCain’s column.”

In advance of Tuesday, it’s simply a question of who you’re inclined to believe more — the most reliable measurement of public opinion in Iowa (along with every other pollster surveying the state) or the McCain campaign’s strategy memo.

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Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.