Senate Majority Leader Mitch McConnell, R-Ky., said Tuesday that the Senate wasn't going to be able to vote on the U.S.-Mexico-Canada Agreement on trade before the end of the year. Postponing the vote until next year means that President Trump may have to get it through a divided Congress, should Democrats regain majorities after the fall election.

"That will be a next year issue because the process we have to go through doesn't allow that to come up before the end of this year," McConnell said on Bloomberg TV Tuesday.

By process, McConnell was referring to Trade Promotion Authority, the law that governs submitting trade deals to Congress. Lengthy negotiations with Canada on the deal caused the White House to miss a deadline to get the current Congress, which expires at the end of the year, to vote on it. The deal can be voted on by the next Congress, however.

Republicans are expected to take losses in the fall elections. RealClearPolitics currently gives the Democrats an advantage of 7.3 percentage points in the generic congressional vote.

It is unclear how the trade deal would fare in Democrat-led Senate or House, but it may still have a good chance of passage as many liberal lawmakers have pointed to positive aspects of the deal.