A bid to quietly include controversial cybersecurity legislation into a must-pass defense policy bill didn’t go unnoticed by the top Democratic judicial authority in the Senate.

Sen. Patrick Leahy (D-Vt.) blasted the procedure as being the result of “closed door” maneuvering involving Senate Majority Leader Mitch McConnell (R-Ky.) and said “the privacy of millions of Americans is at stake.”

He issued the statement on Tuesday, hours after legislation known as the Cyber Security Information Sharing Act (CISA) was introduced as an amendment to a separate amendment to the National Defense Authorization Act (NDAA) by Senate Intelligence Committee chairman Richard Burr (R-N.C.). The underlying amendment concerned background checks for military child care providers.

“I am deeply concerned that the Republican Leader now wants the Senate to pass this information sharing bill without any opportunity for the kind of public debate it needs,” Sen. Leahy said.

Under the legislation, companies would be granted immunity if they share their users’ sensitive information with the government under the auspices of combating cyber crime.

Digital privacy groups like the Electronic Frontier Foundation have argued that the legislation is a “secret surveillance bill” that would open up a new data pipeline to government agencies like the National Security Agency.

Those concerns led to the defeat of similar legislation that was proposed during the previous Congress.

Following last year’s Sony hack, however, the White House reengaged with Congress on cyber-sharing legislation, finding allies on the Senate Intelligence Committee, including Burr and ranking member Sen. Dianne Feinstein (D-Calif.).

In March, the committee passed CISA in a 14-1 vote held in a classified setting.

Leahy is still taking exception to how that procedure was conducted.

“It was considered behind closed doors, without a public hearing or public debate,” he said. That meant lawmakers “cannot even read the text of amendments considered at the mark up of this legislation,” he added.

A vote on Burr’s cyber-sharing amendment could come as early as Wednesday, as the upper chamber slogs through dozens of amendments to the NDAA that are being offered.

CORRECTION: This article was corrected to clarify that the Burr cyber-sharing legislation was introduced as an amendment to an amendment to the NDAA, not an amendment by itself to the NDAA.