The labor groups that represent federal workers have applauded the Senate’s approval this week of a proposal to cap pay for border-security contractors at the vice president’s salary, which is $230,700.

The measure, introduced as an amendment to the comprehensive immigration bill, passed by a vote of 72-26. Twenty-one Republicans supported the proposal, while three Democrats — Sens. Tom Carper (Del.), Tim Kaine (Va.) and Mark Warner (Va.) — voted against it.

“This is an important and sensible first step in reigning in the outrageous taxpayer-funded salaries of federal contractors,” said National Treasury Employees Union president Colleen M. Kelley.

(Victor J. Blue/Bloomberg) (Victor J. Blue/Bloomberg)

The amendment, sponsored by Sen. Joe Manchin (D-W.V.), would affect only contractors for the Department of Homeland Security and the National Guard.

Bipartisan legislation introduced by Sens. Barbara Boxer (D-Calif.) and Charles Grassley (R-Iowa) would extend the cap to all government agencies. Similar legislation from Rep. Paul tonko (D-N.Y.) is pending in the House.

In a statement on Thursday, the American Federation of Government Employees called the combined proposals a “forceful legislative assault on privilege, excess, and conspicuous consumption.”

Contractor advocates have argued that the cap could cause some companies to stop doing government work, in addition to making recruitment and retention harder for them.

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