Utah Sen. Mike Lee is threatening to vote against a spending bill that would prevent a government shutdown this week if the package includes a longterm extension for a surveillance program he fears incidentally spies on American citizens.

Lee stands with another Republican, Sen. Rand Paul of Kentucky — lending some real leverage to the ultimatum as the GOP holds a slim majority in the Senate. The two are asking for debate on Section 702 of the Foreign Intelligence Surveillance Act (FISA), a U.S. data collection effort meant to pick up international communications.

They fear permanent reauthorization for the program, set to expire Dec. 31, could be swept up in the rushed effort to extend government funding, which has the more immediate deadline of Friday at midnight.

“We are not truly secure unless our privacy is respected,” Lee said during a Tuesday news conference.

As it stands, Lee and Paul believe FISA can be abused to prosecute individuals domestically. The two were joined by Republican Sen. Steve Daines and Democratic Sens. Ron Wyden and Patrick Leahy, who suggested the program be certified in the short term before debating potential reform in January.

The group has the support of the American Civil Liberties Union and the conservative advocacy group Freedom Works.

“There needs to be a full-throated debate on reforming, controlling and overseeing this enormous power we allow our intelligence community to have,” Paul said, suggesting FISA employs “less than constitutional” means to collect data.

This isn’t the first time Lee has hinged his support for a spending bill in order to negotiate. In October 2013, Lee was the mastermind behind an effort he hoped would end funding for Obamacare, which didn’t work but led to a partial government shutdown for 16 days.