The White House on Monday vowed to veto a House spending bill for the Justice Department, NASA and several other agencies, charging its GOP authors with violating last summer's budget pact and cutting programs like legal aid to the poor too deeply.

The legislation in question is the first appropriations bill to come to the House floor this year. Republicans are cutting domestic agency operating budgets below levels agreed to with President Barack Obama last year as part of budget legislation setting an overall "cap" on the day-to-day budgets for Cabinet agencies.

A GOP budget plan adopted in March cuts $19 billion below the $1.047 trillion agency budget cap agreed to last year and transfers an additional $8 billion to the Pentagon. The resulting $27 billion cut to domestic agencies has Democrats howling that GOP leaders are breaking a deal they agreed to less than a year ago.

At issue is a $51 billion measure funding the departments of Commerce and Justice, as well as NASA and other science programs. The GOP measure doesn't cut such programs very severely _ just $731 million below Obama's requests _ but the White House has taken a blanket stand that Obama won't sign any spending bills until Republican leaders agree to abide by the deal struck last summer.

GOP leaders like House Speaker John Boehner, R-Ohio, orchestrated the additional $19 billion in cuts as a way to placate conservatives and win enough tea party votes to pass its budget blueprint in March.

The administration opposes cuts to the Legal Services Corp. and for hiring grants for local police departments, among others.

Some Democrats are likely to support the measure despite the veto threat as a way to keep the annual appropriations process on track. They expect Republicans ultimately to agree to the higher levels.