One has nothing to do with the other, unless Brits will vote in our election.
Our nation's founding peoples developed a civic culture that led to our independence, Constitution and legal system, which was largely based on English common law. Those values have become so distorted since WWII, in no small part due to the interference of the EU and globalists like Soros and Obama swanning back and forth between the EU and the US, that our natual alliance has been terribly damaged. This reassertion of British identity, borders and culture can only strenghthen the "America First" spirit championed by Trump.
During the past weeks as I have read the comments sections of the Brit papers, there were plenty of Americans posting encouragement to Leave or warning against Remain, and plenty of Brits addressing Americans and urging us to avoid the islamic cultural jihad enabled by the globalists' "borderless" promotions.
Brexit will enable a President Trump to strenghten our historic alliance in trade, defense and culture with the UK. Brexit will enable the UK to enforce its own limitations on immigration and to diminish its current internal pressures to accept shari'a law. Appeasement or surrender to its large islamic minority (far larger percentage than ours) by the UK would either destroy the advisability of our allying with them successfully, or it would hasten our nation's capitulation to islam.