Comprehensive immigration reform isn't going to happen this year, a Democratic senator said over the weekend.

Sen. Jeff MerkleyJeffrey (Jeff) Alan MerkleyICE has record number of people in custody: report Schumer’s headaches to multiply in next Congress White House-Acosta feud is talk of town MORE (D-Ore.) said he didn't expect a comprehensive bill to make its way through Congress, which returns in September for several weeks of work before breaking again for midterm elections.

The freshman senator said he was working with Sen. Charles SchumerCharles (Chuck) Ellis SchumerSunday shows preview: Trump taps acting attorney general to lead Justice Department Pro-Israel organizations should finally seek payback against Iran deal Dems Pelosi: Acting attorney general 'should not be there' MORE (D-N.Y.) on a bill, but didn't expect it to come up during 2010.

"Sen. Schumer and I are working to bring a package to Congress," Merkley told constituents at a town hall meeting, according to the Salem Statesman Journal. "But reform isn't going to happen this year."

Merkley's acknowledgment reflects a growing pessimism among congressional Democrats that they would be able to tackle immigration reform in any meaningful way this year.

Senate Majority Leader Harry ReidHarry Mason ReidSchumer’s headaches to multiply in next Congress Democrats have a Puerto Rican problem Dem Susie Lee defeats Danny Tarkanian to retain Nevada House seat MORE (D-Nev.) had said back in April, fresh off Democrats' healthcare victory, that the issue must be handled this year, but has since backed off a pledge to take it up. But by the time the August recess rolled around, Reid had backed off plans to pursue a robust bill, and signaled instead that he might seek a scaled-back bill, like the Dream Act.

The backtracking on immigration comes before an election cycle in which some Republicans might look to use the issue against Democrats, even though Democrats are not entirely united on the issue.

The party did move in recent weeks, though, to make itself seem tougher on immigration, with the Senate coming back to convene a special session to advance a $600 million bill to boost border security that the House had passed in a special session of its own.