A proposed “quick reaction force” within the District of Columbia National Guard to protect the Capitol is emerging as a top partisan dividing line for the $1.9 billion security spending bill set for a House vote Thursday.

The top Republicans on both the House and Senate Armed Services committees have come out against the provision, which is aimed at augmenting the defensive response of the Capitol Police.

“Security of the Capitol Complex must remain the responsibility of federal civilian law enforcement,” Rep. Mike D. Rogers, R-Ala., and Sen. James M. Inhofe, R-Okla., said in a joint statement.

The supplemental spending bill would allocate $200 million to the creation of the rapid response team.

“We cannot and should not militarize the security of the Capitol Complex,” Inhofe and Rogers said. “Further, Congress has held precisely no hearings to examine the creation of a Quick Reaction Force to weigh costs, benefits, and fundamental questions about its nature and responsibilities.”

The Armed Services Republicans pointed to an erosion of readiness during what they called an “over-long deployment to Capitol Hill” for Guard troops.

The National Guard Association of the United States also came out against the proposal Wednesday, saying in a statement that “soldiers and airmen should only perform law enforcement as a last resort.”

The association’s chairman, retired Maj. Gen. Michael McGuire, and its president, retired Brig. Gen. J. Roy Robinson, said in a joint statement that a quick reaction force “would be another personnel-intensive requirement on our force as well as a detractor from the Guard’s main mission of serving as the primary reserve of the Army and Air Force.”

The National Guard, which was activated on Jan. 6 and will remain around the Capitol through May 23 to assist Capitol Police, would receive a separate $520.9 million to pay for costs associated with staging troops in and around the building.

As the Capitol was under siege by violent insurrectionists and Capitol Police were overpowered by the mobs on Jan. 6, it took more than three hours for D.C. National Guard troops to be approved for deployment to the Capitol.

Maj. Gen. William Walker, who led the D.C. Guard on Jan. 6 and testified about the delays of his troops, is now the House sergeant-at-arms, the top security official in that chamber.

Inhofe and Rogers’ opposition to the quick reaction force comes after House Republicans spoke out against the proposal Tuesday at a House Rules hearing, saying Democrats were moving forward without Republican input and without agreement on the costs of security needs.

Republican opposition to the bill will likely stall its consideration in the evenly divided Senate, where at least 10 GOP lawmakers are needed to advance legislation.

Jennifer Shutt contributed to this report.