Donald Trump plans a major trade speech on Tuesday that the campaign is billing as "declaring American economic independence," a clear reference to the U.K.'s decision to leave the European Union. If trends continue, he could be doing it against a backdrop of markets crashing and the pound hitting lows last seen in the 1980s.

So far, global market reaction to the Brexit vote, which Trump strongly supported, is yet another nightmare for a campaign that hasn't had a lot of good news lately.

At first the Brexit vote seemed like it could be a boost to Trump, highlighting the power of nationalist sentiment and a desire for less free trade. But the extended market rout — and some second guessing among the British people themselves — suggest it could be quite bad for him.



To be fair, the market chaos that followed the Brexit vote could abate. But most forecasters are slashing their estimates for U.K. economic growth following the vote. The United States is also expected to take at least a small hit. That leaves Trump's argument that Brexit was good for the U.K. and serves as a model for U.S. policy on trade — or anything else — quite a bit harder to make.

Hillary Clinton's campaign is already hammering away at Trump over Brexit. The former secretary of state seized on the issue on Sunday, saying the U.S. needs leaders "who understand that bombastic comments in turbulent times can actually cause more turbulence, and who put the interests of the American people ahead of their personal business interests."



She did not mention Trump. But Clinton was clearly referring to Trump's comments that the plunging pound was good for business at his Turnberry golf course in Scotland. "No one should be confused about America's commitment to Europe, not an autocrat in the Kremlin, not a presidential candidate on a Scottish golf course," she said.

Clinton is also using Trump's Brexit response in a new television ad, part of a national cable ad buy that has so far gone completely unanswered by a Trump campaign that has essentially no money.