But supporters of the treaty, including Sen. John McCainJohn Sidney McCainMcCain rips Trump for attacks on press NSA spying program overcomes key Senate hurdle Meghan McCain says her father regrets opposition to MLK Day MORE (R-Ariz.), are hopeful that some of these senators will relent and support the treaty, which commits countries to expanding access and mobility for disabled people. McCain stressed on Monday that the 36 GOP senators said only that "they would oppose consideration" of the treaty, implying that this is different from saying they would vote against it once under consideration.

Former Senate Majority Leader Bob Dole (R-Kan.) may make an appearance in the Senate today to press for passage of the treaty.

After the treaty vote, the Senate will return to work on the National Defense Authorization Act, S. 3254, and may be able to approve it today after considering more amendments.

The House meets at 10 a.m. for speeches, then at noon for work on just two bills. One is H.R. 6582, which would allow manufacturers to use alternative technologies to meet required energy-efficiency goals.

The other is H.R. 5817, which would allow banks and credit unions to only report their data privacy policies to customers when those policies change, rather than every year. That bill was debated Monday, and the only reason it will be subject to a roll-call vote on Tuesday is because of a request by Rep. Brad Sherman (D-Calif.), who said he thinks House members "ought to spend more time with each other."