Rep. Lou Barletta said one major reason why many of his fellow House immigration critics have been reluctant to propose changes to federal policy is because they do not trust the Senate.

House members fear that any legislative proposal — no matter what the original language — will be used to advance policies they oppose when the other chamber takes it up.

"There is a fear that any bill we pass in the House will be used as a vehicle for a 'pathway to citizenship' in the Senate," the Pennsylvania Republican said Wednesday during a forum on immigration policy at the National Press Club. He did not name any lawmakers who had this fear.

He said the concern was mostly related to when the Senate had a Democratic majority. "There was more fear, obviously, when [Senate Majority Leader] Harry Reid ran things that a bill would be hijacked," he said.

But with Republicans now having the majority in the Senate, that concern has subsided. Barletta said he did not think that a House immigration bill would be re-written in that manner under Senate Majority Leader Mitch McConnell, R-Ky.

But he added that some Republican House members still have concerns even under the current Senate. "Some believe it will, some believe it won't," he said.

Federal legislation must be approved by both the House and the Senate before it can be sent to the Oval Office for the president's signature. Lawmakers pushing a particular bill often call on like-minded members in the other chamber to introduce a bill with the same language to speed the process. If related bills pass but contain different provisions they must be "reconciled" and a composite version created by the lawmakers. That version must be approved by both chambers before it is sent on to the White House.

The reconciled bill can be vastly different from the version that lawmakers previously supported. Lawmakers nevertheless often feel pressured to back the new, different version, which is typically created just before the final vote and thus they have little time to review.

Barletta could not cite any specific instances where a House immigration bill was introduced and a companion Senate version went in a different direction, but said it happens frequently with other legislation. He cited legislation he had introduced to exempt local fire stations from the Affordable Care Act's coverage mandate since firefighters are often volunteers. He introduced it on four occasions only to see companion Senate versions that included entirely different health care-related language.