FRIDAY’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.

* How badly is Florida Gov. Charlie Crist struggling in his Republican Senate primary against former state House Speaker Marco Rubio? The latest Research 2000 poll shows Rubio’s support nearly doubling Crist’s — Rubio 58%, Crist 30%.

* Republicans in Kentucky and D.C. are starting to worry that right-wing ophthalmologist Rand Paul might actually beat Trey Grayson in the Republican Senate primary.

* Sen. John McCain (R-Ariz.) is already facing a tough primary challenge, and now a credible Democrat is eyeing the race: Arizona businesswoman Nan Stockholm Walden.

* In the race to replace the late Rep. John Murtha in Pennsylvania, it looks like Democrat Mark Critz has the early edge.

* In New York, Long Island Democrat Steve Levy announced this morning that he will run for governor as a Republican.

* Speaking of New York, Levy’s gubernatorial GOP primary opponent, former Rep. Rick Lazio, said he will not jump to the Senate race.

* And in still more New York news, the Working Families Party is about to make life much more difficult on Rep. Mike Arcuri (D), now that he’s chosen betrayal and will oppose health care reform after supporting it in November.

* The U.S. Chamber of Commerce intends to spend at least $50 million to elect “pro-business” candidates this year.

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.