Former senator Jim DeMint (R-S.C.) said in an interview broadcast Tuesday that congressional Republicans who oppose the Defund Obamacare effort "should be replaced."

"I'm not as interested in the political futures of folks who think they might lose a showdown with the president," DeMint said at a Monday town hall hosted by Heritage Action, the political arm of the Heritage Foundation, which DeMint leads.

DeMint later told NPR: "I think (President Obama) knows that Republicans are afraid, and if they are, they need to be replaced."

The Defund Obamacare movement seeks to get Republicans to commit to not voting to fund the government if Obamacare is included in that funding.

But several GOP senators have balked at the proposal, not wanting to risk a government shutdown that could be blamed on Republicans.

As a senator, DeMint headed the Senate Conservatives Fund, which challenged several establishment-backed GOP candidates from the right.

At the town hall Monday, DeMint also dismissed a suggestion that the president wouldn't sign a bill the funds the government but doesn't fund Obamacare.

"Well we don't know that, do we?" DeMint said during a question and answer session.