U.S. President Donald Trump’s latest trade upheaval is threatening to deepen his Republican Party’s peril in November’s midterm elections, saddling Senate Republican candidates with another economic headache as the party fights to hold on to its majority.

In recent days, Trump has announced plans for tariff relief on some ground beef imports, enraging cattle producers in states such as Iowa and Nebraska, and launched a new trade war with Canada, rattling manufacturers and businesses in border states including Maine, Michigan, Alaska and Ohio.

Those states are all Senate battlegrounds crucial to Democrats’ strategy to retake the chamber.