The fallout could be significant. An indictment against a company — let alone a conviction — can jeopardize relationships with banks and business partners. The former president is facing down hundreds of millions of dollars in loans that need to be repaid, and the legal threat to his business could deal a blow to his finances. And the charges could play into Mr. Trump’s decisions about his political future. In the past, his grievances have served as both personal motivation and political tool, and as he fought Mr. Vance’s subpoenas for his tax returns all the way to the United States Supreme Court, he added the investigation to the laundry list of legal troubles he recited for supporters. Indeed, some Republicans close to the former president believe he will now be better insulated from those he calls “New York radical-left prosecutors” if he campaigns for president in 2024, and aides said that anger over the indictment could well motivate him to run. But several allies and advisers believe he would not risk losing another general election. On Wednesday, shortly after the indictments were filed, Mr. Trump said at a Fox News town hall that he had made a final decision on whether to run. He did not say what the decision was.