The committee went after Sens. Bill NelsonBill NelsonOvernight Tech: FCC chief poised to unveil plans on net neutrality | Uber eyes flying cars | Media rules under scrutiny Groups urge lawmakers to oppose 'devastating' net neutrality rollback Bipartisan group demands answers on United incident MORE (Fla.), Ben Nelson (Neb.), Claire McCaskillClaire McCaskillFive takeaways from the Georgia special election Picking 2018 candidates pits McConnell vs. GOP groups Potential McCaskill challenger has .7M: report MORE (Mo.), Sherrod BrownSherrod BrownCongress nears deal on help for miners Overnight Energy: Lawmakers work toward deal on miners’ benefits Congress nears deal on help for miners MORE (Ohio), Debbie StabenowDebbie StabenowMedicare’s coverage decisions need more input from physicians Members help package meals at Kraft Heinz charity event in DC Senate braces for fallout over Supreme Court fight MORE (Mich.), Joe ManchinJoe ManchinCongress nears deal on help for miners Senate votes to confirm Rosenstein as deputy attorney general Congress nears deal on help for miners MORE (W.Va.), Tester and Casey in news releases Monday. 

Ben Nelson, a top GOP target in 2012, expressed some disappointment Monday with the president's plan. In a statement, Nelson said the budget proposal "starts the debate about getting spending under control in Washington," but lamented that some of the largest reductions in the plan Obama said would reduce the deficit by $1 trillion over the next decade "arrive in the later years."  

Nelson said he intends to work with senators to "enact spending cuts that kick in sooner," but he didn't offer any detail on specific cuts.

Bill Nelson praised the budget proposal Monday, blasting critics whom he said "offer no real solution and really haven't done any cutting themselves."

"At least the president's budget is a step in the right direction in trying to get this country turned around, to really do something about lowering the deficit and cutting all of this wasteful spending," Nelson told the Bradenton Herald

Brown pointed the finger at Republicans, calling the proposal an effort to "clean up after years of reckless decisions that exacerbated our budget crisis," mentioning the Bush-era tax cuts and wars in Iraq and Afghanistan. 

"By not turing our backs on priorities that promote America's competitiveness — like education, innovation, infrastructure and energy — the proposal is forward-looking and responsible," said Brown.  

No reaction yet to the president's plan from McCaskill or Manchin, both top 2012 targets.  

McCaskill has been championing a plan, along with Sen. Bob CorkerBob CorkerThe Hill's 12:30 Report Senate Foreign Relations chair: Erdogan referendum win 'not something to applaud' Groups warn of rural health 'crisis' under ObamaCare repeal MORE (R-Tenn.), to enact a federal spending cap that she says will cut some $8 trillion from the deficit over the next decade.