MONDAY’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.

* In a major blow to the DSCC, Delaware Attorney General Beau Biden (D) announced this morning that he will not run for the Senate this year. His decision makes it very likely that Rep. Mike Castle (R) will win in November, giving the GOP a key pick-up.

* There was some talk that after the Massachusetts special election, there would be a flood of Democratic retirements. That has not yet happened, but Arkansas Rep. Marion Berry (D) is poised to announce he’s stepping down at the end of his term. He’ll be the 12th House Dem incumbent to retire this year. There are 14 House Republicans retiring.

* Confirming long-rumored plans, former Rep. J.D. Hayworth (R) has decided to give up his far-right radio talk show and take on Sen. John McCain in a Republican primary in Arizona next year.

* In Nevada, a new Research 2000 poll shows Senate Majority Leader Harry Reid (D) trailing his GOP opponents by about 10 points each. If Las Vegas Mayor Oscar Goodman runs as a Democrat, he leads those same Republican challengers by narrow margins.

* A new Ohio Newspaper Poll shows incumbent Gov. Ted Strickland (D) trailing former Rep. John Kasich (R) by six, 51% to 45%.

* With timing running out in Illinois’s Senate primaries, a new Chicago Tribune poll shows state Treasurer Alexi Giannoulias (D) and Rep. Mark Kirk (R) leading their respective fields.

* A new Rasmussen poll shows Sen. Evan Bayh (D) with narrow leads over his Republican challengers, but if right-wing Rep. Mike Pence (R) runs, Rasmussen shows him leading Bayh by three, 47% to 44%.

* Sen. Blanche Lincoln (D) of Arkansas trails state Sen. Gilbert Baker (R), her top GOP opponent, by 4 points in the latest Mason-Dixon poll, 43% to 39%.

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.