In a statement issued Friday, Bishop Gerald Barnes, chairman of the bishops' Committee on Migration, urged national leaders to return to the issue.
"I am deeply troubled that fair and comprehensive immigration reform legislation has failed to move forward in the U.S. Senate," he said.
He continued: "As a nation, we cannot continue to employ an immigration system that leads to the exploitation of millions of our fellow human beings.
"We cannot accept the toil of a large underclass which does not have full rights in our society. This strikes at the very character of our nation and lessens us as a people."
"I urge our elected officials in Congress not to abandon this issue and to return to it as soon as possible," added the bishop of San Bernardino, California. "The status quo is morally unacceptable and should not be allowed to stand."