No matter who is indicted, the move will send shockwaves throughout the Trump administration and the nation’s capital. Until now, the Russia investigation has followed President Trump’s first year in office like a shadow, darkening his political fortunes without substantially altering them. A federal indictment of anyone connected to the Trump campaign or the White House would turn that theoretical danger into hard reality.

The news comes after a week of intensifying conservative criticism of Mueller’s probe. Trump-aligned media figures latched onto a CNN report that Clinton campaign officials had funded the creation of the Steele dossier, an intelligence document on Trump’s Russian ties privately drafted by a British ex-spy in 2016, to try to discredit the overall Russia investigation. (The FBI’s inquiry predates the dossier, and officials have reportedly said it played no role in the intelligence assessment of Russia’s interference in the 2016 election.) Trump himself joined the chorus, claiming on Twitter that former presidential candidate Hillary Clinton should be the real focus of scrutiny.

It is now commonly agreed, after many months of COSTLY looking, that there was NO collusion between Russia and Trump. Was collusion with HC! — Donald J. Trump (@realDonaldTrump) October 27, 2017

The indictment marks a major step forward for the Russia investigation itself. Deputy Attorney General Rod Rosenstein appointed Mueller as special counsel to oversee the Justice Department’s investigation on May 17. The selection capped a two-week political firestorm for the White House after President Trump abruptly fired former FBI Director James Comey on May 9. Trump initially cited the director’s controversial actions in the Hillary Clinton email investigation the previous year to justify the dismissal.

In the days that followed, however, Trump undermined that narrative on multiple occasions. He told NBC News’ Lester Holt that Comey’s firing was related to the Russia investigation, and that he would’ve fired Comey regardless of the Justice Department’s recommendations. He also warned the former director on Twitter that Comey should hope there were no tapes of their White House conversations. In response, Comey asked an intermediary to provide reporters with a series of contemporaneous memos the director had drafted after meetings with Trump earlier in the year.

The memos collectively depicted a president who had little regard for the traditional firewall between the White House’s political operations and the Justice Department’s criminal investigations. In one instance, Comey wrote that Trump asked him to drop the investigation into Michael Flynn shortly after Flynn’s departure as national-security adviser. Trump had fired Flynn, a close but controversial political ally, in February for lying to Vice President Mike Pence and other White House officials about his conversations with Russian Ambassador Sergey Kislyak.