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

* Gallup’s latest congressional poll finds that Republicans still benefit from an “enthusiasm gap” over Democrats in advance of the midterm elections.

* Florida Gov. Charlie Crist is now expected to launch an independent Senate bid. He’ll formally announce his plans at an event tomorrow afternoon in St. Petersburg.

* Speaking of Florida, Marco Rubio (R) seems to be already shifting to a general-election posture, criticizing Arizona’s new immigration law yesterday despite right-wing support for the measure.

* Actor Michael J. Fox is the star of Sen. Arlen Specter’s (D-Pa.) new campaign ad. “Arlen Specter is moving forward,” Fox says. “He’s won the battles to double funding for biomedical research, to find cures and to save lives. He’s smart, tough and always moving forward.” The actor appeared in two Democratic ads in 2006, prompting Rush Limbaugh to mock Fox’s Parkinson’s.

* In Ohio, a new Quinnipiac poll shows Lt. Gov. Lee Fisher pulling away from Ohio Secretary of State Jennifer Brunner in their Democratic Senate primary. Though the two were running close for many months, Quinnipiac now shows Fisher up by 17, 41% to 24%.

* It may not bolster her standing with rank-and-file Democrats, but Sen. Blanche Lincoln’s (D) re-election bid is getting support from the U.S. Chamber of Commerce, which is launching a new campaign ad on her behalf.

* Sen. Joe Lieberman (I-Conn.) is not exactly a reliable Democratic ally, but he has agreed to host a fundraiser in support of Senate Majority Leader Harry Reid (D-Nev.).

* With so much attention on Arizona politics of late, it’s worth noting that Gov. Jan Brewer (R) trails state Attorney General Terry Goddard (D) in the latest survey from Public Policy Polling, 47% to 44%.

* And how far gone are some GOP contingents? Rep. Lynn Jenkins, a far-right Republican in Kansas, is getting a primary challenger. Republican state Sen. Dennis Pyle said Jenkins just isn’t far-right enough.

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.