Sen. Chuck Schumer (D-N.Y.) is again defending Democrats' recent attacks on Charles and David Koch, the billionaire brothers who have spent millions backing conservative candidates and causes.

Appearing on MSNBC's "Morning Joe" on Monday, Schumer said the strategy of going after the GOP megadonors "will work."

"The fact that 48 percent of Americans know who the Koch Brothers are in April... that'll mean about 90 percent of them will know it in October and that's going to be something," Schumer said, referring to a George Washington University Battleground poll released last month.

Democrats have recently aimed to focus voter attention on the influence of the Kochs in the lead-up to the midterm elections this fall. Senate Majority Leader Harry Reid (D-Nev.) has led the charge, accusing the GOP of being "addicted to Koch."

Also appearing on the MSNBC program was The New York Times' Jeremy Peters, who detailed the Democrats anti-Koch strategy in an article published Saturday. Peters compared the Democratic tactics to earlier, largely fruitless GOP attempts to vilify liberal donor George Soros.

Schumer rejected the comparison.

"It's different than George Soros,” Schumer said. “First, the Koch brothers are doing far more with ads than people recognize, and second, they're just real issues, just not ideological issues, but specific issues in the state about them. And I think it's going to make a difference. It's going to undo the sting of a lot of these ads. We're already finding that in the polling in a few of the states."

He continued, "The Koch brothers aren't just sitting there innocently on the side. ... So I don't feel sorry for them. I don't feel their First Amendment rights are being hurt or anything like that."

Schumer noted that attacking the Republican backers couldn't be his party's only tactic as the midterms approach.