WASHINGTON (AP) — A bipartisan push to increase lawmakers' salaries after a decade-long pay freeze is running into predictable obstacles and could be close to unraveling.

The issue has caused a ruckus inside the ranks of House Democrats, where freshmen in politically competitive districts are recoiling at the idea.

The tumult prompted Democratic leaders Monday night to delay action on annual legislation to fund congressional operations, a measure that Republicans used over the past eight years to block a yearly cost-of-living pay increase that lawmakers are supposed to get automatically.

In a statement, the office of Rep. Steny Hoyer, the No. 2 House Democrat, said the legislative appropriations measure was on hold "while we continue to discuss the issue of the cost-of-living adjustment."

The annual COLA has been frozen since the beginning of former President Barack Obama's tenure, and most lawmakers have never received one, including the staunchly conservative Republicans elected since the first tea party wave in 2010.

Rank and file lawmakers make $174,000 per year, a salary that doesn't go nearly as far as it used to, especially with rapidly rising housing costs in the nation's capital. Many lawmakers sleep in their offices during weeks in Washington rather than maintain two homes.

It's a terrible issue for lawmakers, especially Democrats representing tough districts. And the issue has the potential to come up in GOP primary campaigns.

Handling the pay issue has always been an insider's game but fewer and fewer lawmakers are familiar with it. Most of the powerful old timers who helped smooth the controversy in the past and who protected the annual COLA over several years in the early 2000s are long gone.

The pay raise issue dates to a 1989 bipartisan pay reform package in which lawmakers traded a big salary increase and annual inflation adjustments for giving up paid speeches that were abused by top lawmakers. The reforms came unraveled in a mostly forgotten mid-90s battle on an otherwise low-profile spending bill managed by Hoyer, D-Md., who is the chief driving force behind trying to revive the COLA.

Reviving the annual pay raise has to be bipartisan, and Hoyer has allies in top Republicans like Minority Leader Kevin McCarthy of California and GOP Whip Steve Scalise of Louisiana. But the GOP leaders aren't able to deliver the votes to handle the issue as it has been in the past — in which both sides deliver support on an arcane procedural tally in relation to a spending bill.

Hoyer is also encountering skepticism in other Democratic offices, especially after the GOP's campaign arm issued a press release attacking Democrats over the pay issue.

"After campaigning on a slogan of 'for the people,' the socialist Democrats have accomplished a whole lot of nothing 6 months into their majority. And as a reward for their incompetence, they want middle-class taxpayers to give them a $4,500 pay raise! Apparently making $174,000 a year, which is more than three times the average American's salary, just isn't enough for these socialist elitists," read the emailed release from the National Republican Congressional Committee, an organization that answers to top GOP leader McCarthy.

The NRCC has since retracted the statement but it eroded trust between the two sides, which are fighting over impeachment and a variety of other issues in a toxic Washington environment. It was a comparable attack by Democrats in the mid-2000s that upset the detente over the issue.