The Boxer/Casey letter comes months after the senators pushed legislation through the upper chamber that would have barred lawmakers and the president from collecting paychecks if the government had shut down.

Boxer tweeted early Tuesday afternoon: "If #Congress cannot do its job & protect the full faith and credit of the United States, members should not get paid."

The letter to Geithner points out that the Senate had already passed legislation in March on the issue.

Senate Judiciary Committee Chairman Patrick LeahyPatrick Joseph LeahyCongress should build on the momentum from spending bill Overnight Tech: Zuckerberg grilled by lawmakers over data scandal | What we learned from marathon hearing | Facebook hit with class action lawsuit | Twitter endorses political ad disclosure bill | Uber buys bike share Overnight Cybersecurity: Zuckerberg faces grilling in marathon hearing | What we learned from Facebook chief | Dems press Ryan to help get Russia hacking records | Top Trump security adviser resigning MORE (D-Vt.) criticized the bill earlier this year.

The House is expected to vote down a clean vote on raising the debt limit on Tuesday night.