Washington ? In an early showdown for the new Congress, senators are considering setting aside more than 2 million acres in nine states as wilderness.

The largest expansion of wilderness protection in 25 years would include California’s Sierra Nevada mountain range, Oregon’s Mount Hood, Rocky Mountain National Park in Colorado and parts of the Jefferson National Forest in Virginia.

The bill, a holdover from last year, has bipartisan support. Yet it is causing friction that threatens to spoil pledges by Senate leaders to work cooperatively as a new administration takes office.

Sen. Tom Coburn, R-Okla., has pledged to filibuster. He says the spending in the bill is excessive — nearly $4 billion in five years — and that the measure calls for removing millions of acres of federal property from oil and gas development.

Coburn’s objections scuttled the bill last year and have riled Senate Majority Leader Harry Reid, D-Nev. Reid sought to force a rare Sunday vote in an apparent effort to punish Coburn and antagonize his GOP colleagues. The scheduled session would try to limit GOP stalling tactics and move the bill forward.

Reid “runs the Senate like a kindergarten. If we don’t follow his instructions, he keeps the whole class after school,” said Sen. Jim DeMint, R-S.C.

Sen. Lamar Alexander, R-Tenn., one of several Republicans who might skip today’s session, said, “I’m puzzled that Senator Reid would start the year off with a Sunday vote.” If he did show up, Alexander said he probably would vote against moving ahead with the bill, to protest the GOP’s inability to make changes in the legislation.