Bernie Sanders is the front-runner for the Democratic nomination. It is true that the primary has entered a stage where the standings could become very fluid, very quickly. It is also the case that Sanders continues to lag behind Joe Biden nationally. But recent polls have shown Sanders either ahead or a close second in Iowa and the other early states, and his campaign has raised an extraordinary amount of money. With a victory in Iowa, Sanders could well have the momentum and funds to tear through the rest of the primary calendar.

Democratic strategists and commentators late to appreciating Sanders’s viability have spent the past few days diligently making up for lost time, as a cascade of critical stories has appeared in the press. But Republicans, anticipating the general election, are also beginning to take Sanders’s potential nomination more seriously. “There is no mistaking,” a Trump campaign official told Fox News on Monday, “that Bernie Sanders has to be considered the front-runner now.” At an Ohio rally Thursday, President Trump added his own personal touch to that conclusion. “Bernie is going up,” he said. “He’s surging. Crazy Bernie is surging.”

Some of the rhetorical threads Republicans might pursue against Sanders if he’s nominated are already fairly clear. Last week, for instance, the Trump campaign issued a lengthy statement berating Sanders as a “wealthy fossil fuel-guzzling millionaire,” living a life at odds with his messaging on inequality, and criticizing his campaign’s use of jets and office products bought from Amazon. “[H]e’s just another Hollywood-style hypocrite who demands working class Americans make sacrifices while he plays by his own rules and enjoys a lavish lifestyle,” it read. “But Sanders isn’t a celebrity at the Oscars or Golden Globes—he’s the Democrats’ leading candidate for president!”

Republicans have also taken an interest in Sanders’s criticism of the Trump administration’s assassination of Iranian commander Qassem Soleimani, the subject of a strident tweet from the Trump campaign on Sunday. “An Iranian terrorist who killed Americans and orchestrated an attack on our embassy in Iraq was brought to justice,” it read. “But @BernieSanders thinks the terrorist should still be alive, and free to plot more attacks!” On Monday, the campaign told Fox News Sanders is “an apologist for the Iranian regime,” willing to “appease states that support terrorism.”

Outside groups are jumping into the game as well. On Tuesday, James O’Keefe’s ersatz investigative reporting outfit, Project Veritas, perhaps best known at this point for attempting to undermine and discredit The Washington Post’s reporting on the sexual abuse allegations against Roy Moore, posted video of a random Sanders field organizer who speculated about unrest at the Democratic National Convention and defended political imprisonment and reeducation in the Soviet Union.