More than 150 law firms across the country sent a letter to White House budget director Mick Mulvaney on Thursday, urging him not to propose the elimination of federal funding for the Legal Services Corporation.

LSC provides grants to nonprofits nationwide that in turn provide civil legal aid to those who otherwise can't afford it. The beneficiaries of LSC funding include homeless veterans, low-income workers and victims of domestic abuse.

The law firms made the case that defunding LSC would greatly impair legal services provided by nonprofit groups as well as private pro bono lawyers.

"Eliminating the Legal Services Corporation will not only imperil the ability of civil legal aid organizations to serve Americans in need, it will also vastly diminish the private bar's capacity to help these individuals," the letter said.

Mulvaney, who runs the Office of Management and Budget, is expected next week to release proposed budget cuts to offset President Trump's request for a $54 billion increase in defense spending next year.

Those cuts would come primarily from domestic non-defense programs. As part of those, the White House Budget Office will recommend eliminating some agencies from the federal payroll altogether.

Federal LSC funding helps nearly 2 million people a year. But that's just a fraction of the 63 million people estimated to be financially qualified for LSC-funded legal services.

And Jim Sandman, the group's president, told CNNMoney that the vast majority of low-income people have legal civil needs every year. They range from housing problems (such as wrongful eviction or substandard living conditions) to family disputes over child support and child custody to consumer scams. People also need help filing insurance claims after natural disasters or applying for federal lifeline benefits.

While LSC enjoys bipartisan support, the Congressional Budget Office has noted that its critics contend that legal services lawyers "too often focus on social causes rather than on meeting the needs of poorer people with routine legal problems."

Its supporters make the case that the money provided through LSC represents a substantial amount of funding for LSC grantees. The CBO said it remains "the single largest and most important funding source for civil legal services nationally."

Indeed, Sandman notes, more than half of legal aid funding comes through LSC in 12 states, most of which have large rural populations: Alabama, Arizona, Idaho, Indiana, Kansas, Mississippi, Nevada, New Mexico, South Carolina, South Dakota, Texas and Utah.

Sandman fears his group is on the hit list for elimination because he hasn't heard word one from the OMB, a clear departure from prior years.

"LSC has received no response to the budget request we submitted to the Office of Management and Budget last September, even though other agencies are reported to have received responses to their requests last week. It seems to be a signal," he said.

An OMB spokesman said the president's "budget blueprint will be released in mid-March" and it would therefore be premature to comment on the "internal discussion" at the White House.