If you're wondering which Senate candidate might be the next to propose a Brown-Warren style agreement to limit the influence of outside groups, keep an eye on Rep. Tammy Baldwin, D-Wis. In its response to a new attack ad from the Chamber of Commerce, Baldwin's campaign went on the offensive, saying that her GOP opponents should "explain to the people of Wisconsin why they embrace false attacks from DC special interests." With an early fundraising lead and no Democratic primary opponent, Baldwin would stand to benefit politically in the same way Sen. Jon Tester would. -- Another week, another poll showing Democrat Tim Kaine and Republican George Allen neck-and-neck in the Virginia Senate race. In all five Quinnipiac polls since last summer, the margin between the two marquee candidates has been two points or fewer. The poll also echoes a Mason-Dixon poll last month showing a dead heat. With two well-known candidates, it seems clear that -- barring another "macaca" moment or other significant misstep by either candidate -- this race is likely to remain deadlocked into the summer. But one factor -- the popularity of President Obama in the commonwealth -- is trending in Kaine's direction. Obama's approval rating ticked up four points since last December, the Quinnipiac poll showed, and he now holds a slight lead over Mitt Romney in the Old Dominion. Obama's improved standing could lessen the weight of Allen's attacks tying Kaine to the Democrat at the top of the ticket, and it could be a boon to the former Democratic National Committee chairman's chances of holding the seat for his party. -- Wisconsin Gov. Scott Walker might soon have a new and unexpected secret weapon in his effort to hold onto his job: Milwaukee Mayor Tom Barrett. With a recall election all but guaranteed, Barrett, who lost to Walker in the 2010 gubernatorial race, is considering jumping into the Democratic primary. The current frontrunner for the Democratic nomination, former Dane County Executive Kathleen Falk, won the backing of the state's largest teachers union this week, despite the fact that an election hasn't even been officially scheduled and the Democratic field is still in flux. If Barrett, who has a frosty history with labor groups, decides to run, he likely will paint Falk as the hand-picked candidate of the powerful labor movement. This is the same argument that Walker and his supporters will try to pin on Falk (or any eventual nominee). If Falk survives a primary fight with Barrett, she will enter the general election already carrying that noose around her neck. -- This week, 49 state attorneys general reached a mortgage lawsuit settlement with banks that will result in billions of dollars of payment to about 1.8 million borrowers. We're sure to hear a lot about this in coming years as these attorneys general run for higher offices. "I fought the big banks and got you a check" will be a powerful message to voters, whether you're conservative Virginia Attorney General Ken Cuccinelli, who's running for governor, or California Attorney General Kamala Harris, a Democrat pegged for bigger things. -- Ron Barber's Thursday announcement that he is running for former Rep. Gabrielle Giffords's seat instantly made him the frontrunner. Barber has unequivocally cleared the primary field for the special election; and with another endorsement from former Surgeon General Richard Carmona - who shares consultant Rodd McLeod with Giffords and Barber - has further coalesced the party establishment. The outlook is less certain when it comes to the regular election, as Barber hasn't committed to a running in November yet. Further complicating matters are Democratic physician and state Rep. Matt Heinz who seems eager to join the November race, and Air Force combat pilot Martha McSally, a Kennedy School grad and former staffer for Sen. Jon Kyl. -- In the past, ABC has considered joining the ranks of CNN, Fox News Channel, MSNBC and others in the expanding field of cable news. This week, rumors began to swirl once again as Disney (owner of ABC) and Univision begun talks of forming a cable news network, one that would be the first of its kind. While only theoretical at the moment, the partnership means the possibility of a 24-hour news network with at least a partial focus on Latinos, the largest growing minority population in America. An example of Univision's might: In the 18-34 age grouping, it is the third highest rated network. -- One casualty of the contraception debate on the network airwaves was the potential free media exposure the Chamber of Commerce could have received for its $10 million ad buy targeting specific congressional races across the country.