Republicans can move immigration reform forward, Rep. Paul Ryan said Sunday, but only if it puts border security before amnesty for immigrants in the U.S. illegally.

"This is not a trust-but-verify; this is a verify- then-trust approach," said Ryan on ABC.

The Wisconsin Republican added that "we don't trust the president to enforce the law," necessitating strong commitments from Democrats to border security measures in any immigration reform deal. Ryan specifically mentioned border security and interior security that includes a worker verification system and a visa tracking system. Those items have to be in law and independently verified before legalization can move forward, Ryan said.

And the House GOP majority doesn't trust their Democratic counterparts in the Senate enough to allow a bill to go to conference with the Senate, which Ryan said they won't do.

The bottom line: "If we can do that where it's security first, no amnesty, then we might be able to get somewhere," said Ryan. "But I just don't know if that's going to be the case or not."