Senate Democratic leaders today expressed optimism about their prospects of holding on to control of the chamber in November.

The grandest pronouncement came from Senate Democratic Conference Vice Chairman Charles Schumer (N.Y.).

“For this entire Congress, Republicans thought if they blocked anything helping the economy and deprived the president of any accomplishments, it would deliver them a huge political victory in November. Then they could deal with all of the nation’s challenges entirely on their own terms,” Schumer said. “The strategy is backfiring on them.”

A day after the Democratic Conference met with Obama Campaign Manager Jim Messina, Schumer argued that recently revealed comments by GOP nominee Mitt Romney about 47 percent of Americans not paying federal income taxes are having downballot effects that bolster Democratic chances of at least holding the Senate by a thread.

“Their presidential nominee just offended half the country,” Schumer said of Romney. “His flailing campaign is now having a drag effect for Republican Senate candidates across the country, and this has them a little cranky.”

Schumer then pointed to the coordinated speeches this morning by about 30 Republicans on the Senate floor, criticizing Obama and Senate Democrats on a slew of issues including the economy and gasoline prices.

“We have recruited amazing people to run in these Senate races,” said Democratic Senatorial Campaign Committee Chairwoman Patty Murray (D-Wash.).

Murray name-checked as strong Senate candidates Rep. Shelley Berkley (Nev.), Heidi Heitkamp in North Dakota and former Virginia Gov. Tim Kaine. While North Dakota is a Republican majority state, Heitkamp is running to succeed a Democratic Senator, Budget Committee Chairman Kent Conrad.

“I have been so impressed with the people who have stood up to say yes, I do want to serve my country at a difficult time and run in what is an easy thing to do for the United States Senate,” Murray said.

Candidate recruitment has helped the Democrats in some states, along with perceived weakness on the Republican side in some races, but the inverse is sometimes true as well.

For instance, Democrats have a real race on their hands in Connecticut between Rep. Christopher Murphy (D) and Republican Linda McMahon to fill the seat being vacated by Independent Sen. Joe Lieberman.

Nonetheless, “This is not where Republicans thought they’d be with 50 days left before election,” Schumer said.