Healthcare reform will prove a "defining issue" in many of this fall's elections, Senate Republicans' campaign chief said Sunday.

National Republican Senatorial Committee (NRSC) Chairman John Cornyn (Texas) said he expected the healthcare reform bill to be the issue of choice in not only this year's elections, but even in 2012, when President Barack Obama is up for reelection.

"In places like have congressmen who want to be the next senator from Indiana saying they’re going to vote for this bill," Cornyn said during an appearance on "Fox News Sunday."

The House is expected to vote on the bill today, in which a number of lawmakers who are running for Senate seats or governorships are expected to cast a vote. Republicans are all expected to vote against the bill, but Democrats running for other offices may take different positions on the legislation.

Senators will go on record as soon as this coming week, if they can muster a vote on a series of fixes to the legislation.

“That will be the defining issue in that state," Cornyn said, adding that it would be the same of states like New Hampshire, where Rep. Paul Hodes (D-N.H.) is running for Senate.