‚ÄčIt's no secret that deals are an "art form" for U.S. President Donald Trump, who likes making deals, preferably big deals, and promises to cut a very big and exciting trade deal with the U.K. after Brexit.

That window of opportunity is quickly closing in the face of slow-moving negotiations with EU and looming uncertainty behind Trump's reelection in 2020. If Trump isn't reelected in 2020 and voters opt for a conventional candidate, U.K. may face a war on two fronts: fielding resistance from both the EU and a new American Commander-in-Chief.

The establishment view in Washington is pro-European Union. Former Democrat presidential nominee Hillary Clinton didn't mince words when she claimed "Brexit was won on a big lie" and that "Brexit supporters 'voted against modern Britain.'"

Sources close to the president warned the U.K. that U.S. can give a good trade deal only if Britain is free to sign on by 2020, until Trump is in office.

Time is running out.