Saturday marks the completion of Donald Trump’s first year as president. It has been a year of remarkable accomplishments. So why are Republicans in trouble?

Trump signed a tax reform law bolder than the one Ronald Reagan signed in his sixth year in office. He appointed a new Supreme Court justice and set a record for appointments to the federal appellate bench. He rolled back federal regulations and he fulfilled a promise to recognize Jerusalem as Israel’s capital, among many other achievements.

And yet a backlash is coming. Democrats have a good chance to take the House of Representatives in the midterm elections, and may even threaten control of the Senate in a year when Republicans, with few seats at stake, should be growing their majority.

In part, this is just the natural swing of the political pendulum. And since World War II, Americans have generally preferred a divided government to one where one party controls everything. We like Congress to hold the White House in check.

Some of the so-called “Resistance” is also the inevitable result of a presidential election in which the winner was elected by a minority of voters, not only defying expectations but shocking the nation.

In much the same way that outrage over Barack Obama’s election — which would not have happened without help from the mainstream media — partly fueled the Tea Party movement, the anguish of Hillary Clinton’s loss in 2016 has been channeled into protests and activism across the country.

Republicans are also suffering from the complacency — and the disillusionment — of their base. The Senate’s failure to repeal and replace Obamacare cemented the impression that Republican leaders had not only failed their voters, but swindled them.

The evident eagerness of the GOP establishment to offer amnesty to illegal aliens — not just the “Dreamers,” but potentially millions more — has also dampened Republican voters’ enthusiasm to re-elect a Congress that will be led by the same people.

The shutdown theater of the past several days has reinforced an image of Republican incompetence, even though Senate Democrats are to blame. Ironically, Speaker Paul Ryan (R-WI) has managed the House well. But the Senate GOP’s NeverTrump faction — led by outgoing Sen. Jeff Flake (R-AZ), who likened Trump to Stalin this week — has divided and damaged the party.

Yes, the GOP pulled itself together to pass tax reform. Many Americans will soon notice that they have extra money in their paychecks.

The problem is that much of that cash will have to go towards rising health insurance premium. The average Obamacare premium will be about $800 higher in 2018 — for benefits many people cannot even use, because of high deductibles. That will eat up half the average tax cut of $1,600. And Republicans failed to lower costs as promised.

Democrats are making the most of the opportunity by talking about health care at every opportunity. In contrast to President Trump’s claim that voters would blame Democrats when Obamacare began to implode, voters prefer Democrats to manage health care — by a double-digit margin.

People know that Democrats’ solutions will not work, but at least they are talking about solutions. Republicans are resting on their laurels after repealing the individual mandate, which is irrelevant to most people.

Then there is the #metoo movement, which has fed into a feminist backlash against Trump going back to the “pussyhats” and the Women’s March last January. Though most of the perpetrators of sexual harassment and assault have been liberal Democrats, Republicans are the party in power.

Women who intend to use their votes to make a statement are going to make it against the ruling party. Democrats have also recruited a large number of new female candidates to run for office.

Finally, there is Trump himself. Obama was a divisive president, who waged class warfare and broke the rules of the Constitution for the sake of socialism at home and appeasement abroad. But Trump has taken the politics of confrontation a step further in the way he attacks political rivals, often through social media.

Though controversy is good for the news business, many Americans are tiring of the daily drama.

These are the reasons for the coming backlash.

With Democrats surging, talk of insurgency in Republican primaries has faded — especially after Roy Moore’s defeat in Alabama. People feel less inclined to stoke internal fights when the general election is in doubt.

There are exceptions, where the incumbent Republican is likely to win — or to lose. An example of the latter is in Illinois, where Governor Bruce Rauner buckled on taxes and abortion. He faces a primary challenge from a solid — but long-shot — candidate, State Senator Jeanne Ives.

Regardless, Republicans are in trouble. The party’s message for 2018 will be less about the achievements of the past two years, and more about preventing Trump’s impeachment and keeping the Speaker’s gavel out of Nancy Pelosi’s hands.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He was named to Forward’s 50 “most influential” Jews in 2017. He is the co-author of How Trump Won: The Inside Story of a Revolution, is available from Regnery. Follow him on Twitter at @joelpollak.