The weekend saw a new phase of open attacks by President Trump on special counsel Robert S. Mueller III’s investigation. The president spent both Saturday and Sunday mornings ranting on Twitter against the probe, before worried aides “decided to whisk Trump to a golf course.” On Saturday, Trump’s personal lawyer John Dowd called on Deputy Attorney General Rod J. Rosenstein to “bring an end to alleged Russia Collusion investigation manufactured by McCabe’s boss James Comey.” On CNN’s “State of the Union” Sunday, Sen. Lindsey O. Graham (R-S.C.) told moderator Jake Tapper that Americans shouldn’t fear: If the president fired Mueller, “that would be the beginning of the end of his presidency, because we’re a rule-of-law nation.” Sen. Jeff Flake (R-Ariz.) echoed that: “I would expect to see considerable pushback in the next couple days in urging the president not to go there.”

Graham and Flake may believe that, but they’re wrong: As long as Republicans control Congress, Trump can do what he wants. The end will begin only at the ballot box.

More than a year into Trump’s presidency, there’s nothing to suggest Republicans will hinder Trump from firing Mueller and/or ending the Russia probe. Indeed, Flake and Graham’s GOP colleagues offered little to suggest Congress could or would block the president. Asked how he would respond to Mueller’s firing, Sen. Rand Paul (R-Ky.) told Tapper, “Well, I have said all along I don’t like special prosecutors.” On “Fox News Sunday,” Rep. Trey Gowdy (R-S.C.) did advise the president not to shut down the investigation but also pointed out that “I’m not sure the House can do a lot” to stop Trump from doing that. On ABC’s “This Week,” Sen. James Lankford (R-Okla.) was similarly unable to name anything Senate Republicans could do to stop Trump’s attacks on the probe or a potential shutdown.

 The GOP’s supine behavior should not surprise anyone. When Trump’s term began, some Republicans still feared that he would work with Democrats and push policies that the GOP couldn’t support. With tariffs being the lone exception, Trump has proved to be reliably Republican, and he remains overwhelmingly popular with the party’s base. As long as the president keeps signing tax cuts, slashing regulations and appointing conservative justices and judges, there’s little reason for most Republicans to push back against him.

Furthermore, while Flake, Graham and others have verbally criticized the president, they have yet to vote against the president and the party in crucial moments. Assuming that pattern holds, if Trump fired Attorney General Jeff Sessions and replaced him with a GOP stalwart (say, Scott Pruitt, now administrator of the Environmental Protection Agency), these senators would likely criticize the firing before voting for the president’s choice anyway.

The historical record also suggests a Republican majority will leave the president essentially unrestrained. When Democrats wanted an investigation into President Richard Nixon’s White House and the break-in at the Watergate Hotel, Republicans dismissed the allegations. They even suggested probes instead look into the 1964 and 1968 elections, misdirection similar to modern Republicans’ calls for a probe into the FBI. The difference? Democrats, not Republicans, controlled the House and the Senate. They forced Nixon to greenlight appointing an independent prosecutor, and they were the party that held Nixon accountable. Even in July 1974, one month before Nixon’s resignation, a majority of Republicans on the House Judiciary Committee voted against every article of impeachment. Only one Republican voted for all three approved articles: Maryland Rep. Lawrence Hogan — and he lost the GOP primary for Maryland governor because of that courageous stand.

As Watergate shows, what Trump does about Mueller or the probe doesn’t matter unless Democrats retake at least one of the House or the Senate. Then, Democrats will be able to use the committees’ tremendous powers and their leverage over the legislative agenda to hold the president accountable. Whatever “end” the Trump presidency comes to, the road to it starts at the midterms.

After Trump’s Sunday tweetstorm subsided, the New York Times’s Maggie Haberman tweeted that Trump is “testing what Hill [Republicans] will let him get away with” regarding Mueller. She added, “This does not mean he will fire Mueller – but it raises increasing prospects that he orders/pushes Rosenstein/Sessions to do so.” Graham and Flake may believe doing so would cost the president — but all the evidence suggests their hope remains foolish.