Mr. Trump’s cash crunch marks a stark reversal from the 2012 presidential campaign, which seemed to inaugurate a new era of virtually unlimited money in American politics, buoyed by the Supreme Court’s Citizens United decision two years earlier. By the same point that year, President Obama and Mr. Romney were raising tens of millions of dollars per month with their parties. And while Mr. Romney faced a larger deficit overall against Mr. Obama in June 2012, he was raising far more money than Mr. Trump is now, with big donors flocking to his cause.
“The campaign has got to be the entity that’s out there driving the fund-raising car,” said Austin Barbour, a lobbyist who served as national finance co-chairman of the Romney campaign. “And it better be a big old Cadillac.”