Washington ? It’s not a question of whether but how Sen. Mitch McConnell will seek to sidetrack the campaign finance reform bill that passed the House this week.

He may filibuster, he may go to court or he may do both.

“I still have two options that are not mutually exclusive,” said McConnell, R-Ky., who has successfully led opposition to previous reform attempts.

Scott Harshbarger, president of the pro-reform advocacy group Common Cause, is taking nothing for granted.

“He is a very skilled and worthy adversary,” Harshbarger said of McConnell. “He’s very knowledgeable. I disagree with him but I never, never would underestimate him in this upcoming battle.”

The House bill, approved Thursday, would ban corporations, unions and individuals from making large, unregulated donations to political parties and restrict unions, corporations and some independent groups from broadcasting issue ads within 60 days of an election or 30 days of a primary.

McConnell says the bill violates free-speech rights and weakens the political parties by limiting their spending abilities. He also believes it favors Democratic candidates since they get a lot of help from unions, which would still be able to use member dues to run political ads and grass-roots activities.

He plans to spend next week’s congressional break studying the House bill, looking for places to attack. “This is a situation where every bit of the language makes a difference,” McConnell said.

Slightly different legislation passed the Senate 59-41 last year. Senate Majority Leader Tom Daschle, D-S.D., said the Senate would consider the House measure rather than forming a conference committee to work out a compromise.

Forcing a conference committee, where McConnell thinks he would be able to reshape the bill, would require him to stage a filibuster. The delaying tactic can kill a bill even before lawmakers vote on it. McConnell would need 40 senators to back him.