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

Sen. Jeff MerkleyJeffrey (Jeff) Alan MerkleyDem senator: If Nielsen doesn't reunite families, 'she should resign' Senate Dems call for Judiciary hearing on Trump's 'zero tolerance' GOP lawmaker compares cages for migrant children to chain-link fences on playgrounds 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 SchumerDonald Trump Jr. headlines Montana Republican convention Montana's environmental lobby teams with governor to kill 600 jobs Dems allow separation of parents, children to continue, just to score political points 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 ReidAmendments fuel resentments within Senate GOP Donald Trump is delivering on his promises and voters are noticing Danny Tarkanian wins Nevada GOP congressional primary 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.