"The American public is seeing that and feeling that and it is definitely changing the landscape in front of us," she said.

In two of the states Democrats are targeting as potential pickup opportunities, incumbent Republicans face potentially tough primary challenges and Murray said the DSCC has decided to aggressively recruit in both.

She cited Delaware's 2010 Senate race, in which Tea Party-backed Republican Christine O'Donnell upset longtime Rep. Mike Castle (R-Del.) in a primary and then went on to lose by a wide margin to Democrat Chris CoonsChris CoonsDemocrats go in for the kill on ObamaCare repeal Funeral for the filibuster: GOP will likely lay Senate tool to rest Overnight Regulation: Labor groups fear rollback of Obama worker protection rule | Trump regs czar advances in Senate | New FCC enforcement chief MORE.

Murray pledged to have strong challengers already in place and organizing in both Indiana and Maine should either Sens. Dick Lugar (R-Ind.) or Olympia Snowe (R-Maine) fall short in their respective primary campaigns.

"You ask Sen. Coons whether I should sit back and see how that primary plays out or whether we should get in and find a candidate," said Murray, who praised Rep. Joe DonnellyJoe DonnellyIndiana GOP rep: Likely primary opponent 'lying about my family' Dem senator to sell stock in family company that uses outsourced labor Vulnerable senators raise big money ahead of 2018 MORE (D-Ind.) as an "aggressive candidate" who has won "tough campaigns."

Murray said she's spoken to Donnelly about an Indiana Senate bid and said she expects the party to have a candidate in the state soon. Donnelly has said publicly that he's leaning toward a statewide run given that his congressional district will lean more Republican next year once new district lines are drawn. 

Murray also promised a candidate "soon" in Texas, where she said changing demographics offer the party a chance to pick up the seat of retiring Sen. Kay Bailey Hutchison (R-Texas).  

As for Arizona, Murray said Democrats were giving Rep. Gabrielle Giffords (D-Ariz.) and her family "all due respect to recover from a very serious trauma," following the shooting that severely wounded the lawmaker earlier this year.

"None of us can predict what Congresswoman Giffords will do," Murray said, but she expressed confidence that the party will have a strong candidate in the race.

Murray also said she's confident that there will be no more Democratic retirements ahead of 2012. Retirement speculation still surrounds Sen. Herb Kohl (D-Wis.), who has not officially announced his 2012 intentions.   

The National Republican Senatorial Committee pushed back on Murray's message, calling national Democrats "oblivious to the reality" of 2012.

"While national Democrats appear oblivious to the reality that a number of their incumbents are running in red states next year, Republicans can only hope they continue to demand that every one of their candidates toe the party line in favor of higher taxes, more spending and a record debt," NRSC spokesman Brian Walsh said in a statement.

Despite the optimism from Murray, Democrats face a tough slog next year. Should President Obama win reelection, Republicans need to pick up just four seats in 2012 to win control of the upper chamber.