As Republicans file back to Washington from their convention in St. Paul, Minn., a senior GOP aide said they may continue to block Senate Majority Leader Harry Reid (D-Nev.) from taking up any legislation unrelated to reducing prices at the pump.

Before the Senate left for its summer break, Senate GOPers prevented the chamber from moving off a Democratic oil speculation bill when Reid tried to proceed toward the Defense authorization bill as well as a handful of bills held up by Sen. Tom Coburn (R-Okla.).

The aide speculated that such action could continue unless Reid allows Republicans to file amendments related to offshore drilling.

Republicans have charged that Democrats are not serious about doing something to bring gasoline prices down and would thwart any movement on legislation not seeking to do so.

Their moves created a political standoff between Reid and Senate Republicans, and have so far soured a possible deal on the Democratic leadership’s oil speculation bill.

With only three weeks left to get a host of bills completed, a continued GOP filibuster could upend the continuing resolution necessary to avoid a government shutdown on Oct. 1, the first day of the new fiscal year.