President Trump on Friday called for his biggest supporters to avoid complacency ahead of this year’s midterm elections, saying they need to stay engaged and rally behind congressional Republicans.

In a 75-minute speech at the annual Conservative Political Action Conference held just outside Washington, Trump acknowledged the historic difficulties faced by a president’s political party in off-year campaigns following presidential elections and urged his supporters not to be complacent.

“What happens is you fight so hard to win the presidency, and you fight, fight, fight,” Trump said. “By the time you start campaigning, it's a year. And now you got to go and fight again. But you just won. So nobody has that same drive that they had.”

The president volunteered the fact that Democrats are highly energized against him -- “they’re crazed,” as he put it -- while calling on his voters to marshal similar levels of enthusiasm.

“You're sitting back, you're watching television. ‘Maybe I don't have to vote today. We just won the presidency.’ And then we get clobbered,” Trump cautioned. “We can't let that happen.”

The speech, given in front of die-hard Trump supporters and conservative activists, was reminiscent of Trump’s 2016 campaign rallies. It included calls from Trump to build a wall on the Mexican border, along with "Lock her up!” chants from the audience when the president mentioned Hillary Clinton. It also touched on a variety of current issues, such as touting tax cuts signed into law late last year, criticizing Democrats over the lack of an agreement on immigration, and pushing for a response to the school shooting in Parkland, Florida last week -- with most of Trump’s emphasis placed on school security, including allowing some teachers to carry guns.

But Trump consistently returned to the midterm elections and his hope that his supporters will stay engaged. The Democratic Party base was energized throughout 2017, with strong turnout in off-year elections helping them secure victories in a number of statewide and local races, even in GOP territory -- a mini-wave that Democrats hope will swell into a tsunami this year. Trump remains immensely popular with his supporters and the GOP base, however, which means that preserving their congressional majorities depends on the ability of Republican incumbents and challengers to transfer enthusiasm for Trump into votes for themselves -- even when the president’s name isn’t on the ballot.

The effort will be particularly necessary in Senate races, with 10 Democrats running for re-election in states Trump carried in 2016, including five he won overwhelmingly. But Republicans in House races, facing an energized and organized opposition from Democrats, could be facing serious problems if Trump supporters don’t turn out in force. Democrats need to win 24 seats to flip the House majority, and The Cook Political Report, a nonpartisan election analysis, currently rates 26 GOP seats as either toss-ups or favoring Democrats.

After touting tax cuts, his success at confirming a Supreme Court justice and lower court judges, and his support for the Second Amendment, Trump warned his audience that all those issues would be in jeopardy if Democrats won back control of Congress.

“Don't be complacent, because if they get in, they will repeal your tax cuts,” Trump said. “They will put judges in that you wouldn't believe. They'll take away your Second Amendment, which we will never allow to happen.”

“I’d love you to get out there and work really hard for '18,” he later added. “We need more Republicans to keep the tax cuts and keep all of this going.”