Julian Zelizer is a history and public affairs professor at Princeton University and the author of " The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society ." He's also the co-host of the " Politics & Polls " podcast. The opinions expressed in this commentary are his own.

(CNN) President Donald Trump loves the imperial presidency. His explosive pardon of Sheriff Joe Arpaio was meant to send a signal to the base about immigration policy but also to demonstrate that he is willing to flex his presidential muscle however he sees fit.

He will pardon people, he will use executive powers -- like the transgender ban in the military -- and he will make decisions about foreign policy on his own. The man who inhabits the Oval Office is a person who sees no restraints on his power and who does not believe any other branch of government can get in his way.

This is why he has spent the last few weeks going after the Republican Congress.

He has lashed out against Republicans who have been critical of him, like Senator Jeff Flake and Senator Dean Heller, while in Phoenix he announced that he was ready to go to the mat and send the nation into default if Republicans in Congress don't give him the money that he needs to build a wall.

On Thursday, he unleashed another tweetstorm attacking the GOP. According to the Washington Post, the administration sees this as a winning strategy. If Republicans do poorly in the 2018 midterms, he can blame them. "The Trump brand and the Republican brand are two different things," explained Roger Stone

Senator McConnell, who according to the New York Times, privately doubts if Trump can salvage his presidency after this disastrous summer, seems to be preparing for battle.

But the President needs to be careful. Most of our presidents discover at some point that they are not quite as imperial as they think. If this intra-party battle royale actually does continue, President Trump could find himself on the losing end. Congress still has the ability to cause immense damage to a president -- even when it is controlled by the same party.

An angry Congress can accelerate televised investigations into an administration, can stifle any progress on legislation and send the president bills that he is either forced to veto or sign because of political pressure, and they can use their own smaller bully pulpits on television to discredit the President and drag down his approval ratings, which, in Trump's case, are already low.

There have been many times when presidents wound up losing battles against their own party. In the 1930s when Democrats generally ruled Congress, Franklin Roosevelt famously did battle with conservative southern Democrats. He tried to purge some of them in the 1938 midterm elections.

FDR was generally unsuccessful, which meant that the conservative southern Democrats who he actively campaigned against by supporting their primary opponents were back in 1939 and, teaming up with Republicans, formed a conservative coalition that blocked progress on much of his domestic agenda.

After the 1966 midterm elections, a newly enhanced conservative Democratic Congress tied Lyndon Johnson up in knots, preventing him from moving forward on some Great Society programs and forcing him to confront the budgetary costs of the Vietnam War.

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Democratic legislators became some of Johnson's most vocal and problematic critics of the war, leading to a number of primary challenges to the president's re-election bid in 1968 before he decided to withdraw from the race.

Presidents Jimmy Carter and Bill Clinton both learned that unified government did not mean inevitable victory. Carter found himself in combat with traditional northeastern Democrats who would not support his centrist agenda while Clinton's health care plan went down to defeat because many members of his own party would not endorse his plan.

President Trump is more vulnerable than most. His unorthodox and controversial style of politics creates more political incentives for Republicans to take a stand against his presidency. When a president offers sympathetic words about white supremacists and pardons a person like Arpaio before he is even sentenced or seriously vetted by the Justice Department, the costs of a member of his own party putting forth a challenge are much lower than in normal times.

President Trump's disastrous legislative record and miserable national approval ratings create more than enough reason for Republicans to strike back when the president goes after them. While it is true that Trump remains in pretty good shape among Republican voters in the polls, it is reasonable for legislators to assume those numbers are soft and that it would not be difficult to build a case for saving the party by taking on this divisive and, to some unfit, leader of our nation.

President Johnson liked to say that Congress eventually got the best of every president -- and he was talking in an era when his own party, the Democrats, controlled both chambers. Although President Trump likes to imagine that his blindly loyal base is the political force that keeps him in power, he should not be so delusional as to forget that it was the entire Republican Party that brought him to the White House.

Without broad partisan support from the GOP, Trump would not have won the election nor would he have enjoyed the kind of political insulation thus far that would have been unimaginable for any other president who has said and done the kinds of things that we have seen from his White House.

The real question is not whether President Trump could end up severely damaged by a fight against his own party, but whether the congressional wing of his party really has the courage or political interest to take him on when push comes to shove.

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With the budget battle this fall and the struggle over raising the debt ceiling, we might be reaching a point whether we finally learn whether the GOP is going to stand up to the radical ways in which Trump is trying to reshape our political culture or, whether in the end, they will simply back down.

If the Republican Congress decides to take on a president from their own party, history shows that they have more than enough tools at their disposal to check and undercut him in way that no other institution can do. The way they respond to his attacks on them will define how the history books remember the Republican party at this crucial moment for our nation.

And if the President really spends the next few months attacking the Republican Congress and succeeds in undercutting enthusiasm within his base,he might regret his actions by finding himself with a Democratic Congress in January 2019 that is more than willing to move forward with impeachment.