The nation’s political battleground shifted to the stock market this week, as Commerce Secretary Howard Lutnick urged people to buy shares of Tesla Inc. and Minnesota Gov. Tim Walz mocked the electric-vehicle giant’s share-price drop.

The former vice presidential candidate Walz said he checks Tesla’s share price to give him a “little boost during the day,” nodding to Musk’s company’s more than 40% year-to-date loss.