For many of Trump’s primary rivals, the case against nominating the former president was straightforward: He could not defeat President Biden in a general election, when more moderate and independent voters are needed to prevail in key battleground states. But recent polling has dealt a blow to that argument. Polls from The New York Times, CNN, CBS News and Emerson College have shown Trump leading Biden in a hypothetical 2024 matchup both in key swing states and at the national level. “The electability argument is gone for others,” said one former Trump White House official. Former South Carolina Gov. Nikki...