A top Obama administration adviser said he is optimistic about Democratic prospects in the November elections, arguing that voters realize Republicans "contributed nothing."

David Axelrod, senior White House adviser, said on NBC's "Meet the Press," that Democrats are mounting a large scale midterm effort to ensure the party maintains control of the House and Senate.

"They have rooted for failure," Axelrod said of Republicans. "They have contributed nothing."

Axelrod said Democrats have a strong record of casting "courageous votes."

The $787 billion fiscal stimulus package and healthcare law are among the top issues in the election, alongside broader concerns about the economy.

The economy is growing, but economists have noted mixed signals with 9.7 percent unemployment and continued concerns in housing markets. Private sector job growth was slim compared with the more than 400,000 jobs added because of the 2010 census.

On ABC's "This Week," House Majority Leader Steny Hoyer (D-Md.) predicted Democrats would retain control of the House.

House Minority Leader John Boehner (R-Ohio) said on the same program that Republicans consider 100 House seats to be in play.

"We have a real shot of winning the majority," Boehner said.