When discussing swing states and potential swing states, I sometimes joke with people that once a year or so, there’s a poll that shows the Republicans looking surprisingly good in Oregon, and then the Democratic lead reappears as Election Day approaches.

Looking back, that poll appears to usually come from Survey USA.

In 2004, Survey USA had President Bush ahead of John Kerry by a single point on September 21. Mason-Dixon had Kerry ahead by a single point on October 18.

On Election Day, Kerry won, 51 percent to 47 percent.

In 2008, Survey USA had Barack Obama ahead of John McCain by three percentage points on August 4.

On Election Day, Obama won, 57 percent to 41 percent.

Oregon’s teasing poll appears to have arrived early this year: “In a November match-up between Barack Obama and Mitt Romney for President of the United States, Obama today edges Romney, 47 percent to 43 percent.”

This isn’t necessarily a flaw in the polling of SurveyUSA; Oregon may be one of those states where they voters are never all that satisfied with the options before them, and thus a Democratic candidate can sporadically find himself in the mid-40s… but it’s still a heavily Democratic state, and most of those voters “come home” to their traditional party.

Having said that, there’s some indication that Oregon is significantly less Democratic than it was last time Obama was on the ballot, according to Gallup. In 2009, their samples found 51 percent of Oregon voters identifying themselves as “Democrat.” By 2011, that was 44.3 percent. Meanwhile, Republicans jumped from 34.8 percent to 40.3 percent.