WASHINGTON — Emboldened by President Bush’s threat to veto a Democratic plan to help homeowners in danger of foreclosure, House Republicans threw up repeated roadblocks to delay debate of the legislation on Wednesday, prompting an angry argument between party leaders over procedural tactics.

House Democrats, led by Representative Barney Frank, Democrat of Massachusetts and chairman of the Financial Services Committee, had been hoping to build a bipartisan consensus on the housing legislation, which would widen the availability of federal-insured mortgages to help troubled borrowers refinance their loans.