WEDNESDAY’S CAMPAIGN ROUND-UP…. Today’s installment of campaign-related news items that wouldn’t necessarily generate a post of their own, but may be of interest to political observers:

* In Maine, the easiest path for Sen. Olympia Snowe to win re-election is to leave the Republican Party and run as an Independent. Whether she’s open to the idea remains unclear.

* Karl Rove’s American Crossroads operation is launching a new anti-union ad campaign, spending $750,000 in unreported funds on national attack ads targeting public service unions and President Obama. The spots will run this week on CNN, CNBC, and Fox News.

* Behind the scenes, there’s intense competition underway between likely Republican presidential candidates to hire top-tier campaign aides. With that in mind, it’s noteworthy that Mississippi Gov. Haley Barbour’s political action committee hired former RNC communications director Jim Dyke.

* The good news for Sen. Claire McCaskill (D-Mo.) is that a new statewide poll shows her leading her likely GOP challengers. The bad news is, the margins of her leads are tiny, despite the fact that most Missouri voters don’t even know who those Republicans are.

* Will former governor and DNC chair Tim Kaine run for the U.S. Senate in Virginia? Recently departed Virginia Democratic Party Chairman Dick Cranwell thinks he will.

* Will Wisconsin Sen. Herb Kohl (D) be the next Senate incumbent to retire? There were clearly hints in that direction yesterday.

* Attorney Byron Georgiou is the first Nevada Democrat to launch a U.S. Senate campaign in the wake of Sen. John Ensign’s (R) retirement announcement, but he’s not at all well known by party leaders.

* Sen. Bob Menendez (D) is a likely favorite in his re-election bid next year, but as his first term comes to an end, a plurality of New Jersey voters still don’t have an opinion about him.

* In light of his recent mental health problems, Rep. David Wu (D-Ore.) is finding that most of his constituents don’t want him to remain in office.

* And in Massachusetts, former Rep. Joe Kennedy (D) has made clear, once and for all, that he will not take on Sen. Scott Brown (R) in 2012.

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.