Federal lawmakers are quietly pushing for the continued expansion of temporary guest worker visas that let foreign nationals work low-wage jobs in the U.S. Some senators and representatives on both sides of the aisle are pushing to keep measures put in place last year that effectively quadrupled the number of such visas.

The Republican and Democratic lawmakers, who are far apart on most issues, come chiefly from states that rely on the H-2B guest worker visas to fill employment rosters. Nine members of the House sent a letter to the Appropriations Committee last week urging that the visa levels remain.

“Many businesses will be severely impacted, and some may be unable to operate, without this cap relief,” said the letter, which Politico obtained. The letter was addressed to Reps. John Carter, R-Texas, and Lucille Roybal-Allard, D-Calif.

The visas provide a legal path to work for foreigners who take up such jobs as landscaping, housekeeping and seafood processing. The visas were capped at 264,000 during last year’s omnibus budget negotiations. Previously the limit was set at 66,000, a quota that business advocates say is an arbitrarily low number with the potential to hurt American industries that rely on foreign workers. The visas allow a maximum stay of three years.

Democrats and Republicans do not generally agree on the issue, with many in the GOP supporting the visas, while Democrats criticize what they see as inadequate protections for the workers under the system.

Some critics argue the program hurts American workers. 

“It’s frustrating that any of the [lawmakers] would push this,” said Sen. Jeff Sessions, R-Ala., a vocal critic of the program and the only senator who has yet endorsed Donald Trump. Sessions is among Congress's top hard-liners on immigration and has argued that the H-2B visa program increases American unemployment and depresses wages.

"The program does not need to be expanded. If anything, it needs to be constricted,” he said of the new effort to maintain high visa levels.

The fresh push on Capitol Hill comes amid a contentious presidential election season that has brought tough immigration talk to the fore. Trump has made immigration a pillar of his campaign, promising to deport undocumented immigrants from the country and building a wall on the Mexican border. Trump has defended the use of H-2B visas in his own businesses and has promised a reworking of the immigration laws.

Democrats, including former Secretary of State Hillary Clinton and Vermont Sen. Bernie Sanders, have taken a more inclusive attitude toward undocumented immigrants. Both have called for deportation relief for some undocumented immigrants.