In the last few days Trump has made a high profile push for making schools "hard targets" for gunmen, including supporting the arming of teachers.
That came in the wake of America's worst ever high school shooting when 17 people died in Florida last week.
He continued those calls in a freewheeling, hour-long campaign-style speech at the Conservative Political Action Conference near Washington on Friday.
At the biggest annual gathering of conservative activists Trump abandoned his script, in which he had been expected to announce new sanctions on North Korea.
Looking from the stage at an image of himself on a big screen, he said: "By the way, what a nice picture that is. Look at that.
I'd love to watch that guy speak!" Trump then turned around and put his hands on the hair at the back of his head, admiring it on the screen.
He told the crowd: "Oh, I try like hell to hide that bald spot, folks. I work hard at it. It doesn't look bad. Hey, we are hanging in, we are hanging in. Together, we are hanging in."
The president added: "By the way, you don't mind if I go off script a little bit, because, you know it's sort of boring."
In scenes reminiscent of his campaign rallies Trump referred to "crooked" Hillary Clinton, his opponent in 2016, which sparked chants of "Lock her up" from the crowd.
At one point, a protester was removed after throwing a Russian flag towards the stage.
The crowd of mostly young activists chanted "USA, USA" as the protester was ejected by security "They were very gentle. He was very obnoxious," Trump said.
He then attacked the assembled media for spreading "fake news" and vowed to "build the wall 10ft higher" every time someone objected to it.
Trump called Democrats "crazed" and warned his supporters the Democrats "will take away your Second Amendment", the right to bear arms.
He warned complacency would lead to Republicans being "clobbered" in upcoming Congressional elections in November. "Don't be complacent because if the Democrats get in they will repeal your tax cuts," he added.
Trump asked the crowd of hundreds of people if they could have only one of tax cuts, or the Second Amendment, which they would choose The overwhelming majority cheered for the Second Amendment and he nodded his approval.
Trump added: "I think now we've proved I'm a conservative." He also publicly shamed an armed officer who failed to act during the Florida school shooting.
Trump condemned Scot Peterson, a sheriff's deputy who was on duty and in uniform as the resource officer posted to Marjory Stoneman Douglas High School.
It emerged that Peterson, 54, stood outside the building where the shooting happened for four minutes as Nikolas Cruz, 19, gunned down fellow teenagers.
Trump said: "Deputy Sheriff Peterson, I guess his name is...What he did, he's trained his whole life when it came time to get in there and do something, he didn't have the courage or something happened.
He heard it right from the beginning so he certainly did a poor job." The US president added that Peterson "didn't act properly under pressure" or "was a coward". He said the officer was "not a credit to law enforcement".
Trump added that he would rather have had teachers armed with concealed weapons at the scene.
He suggested up to 20 per cent of teachers, and school staff such as sports coaches, were "gun-adept" and could be armed. That would be more than half a million teachers.
Trump said: "A teacher would have shot the hell out of him (Cruz) before he knew what happened. I'm telling you that would work. "These teachers love their students, and these teachers are talented with weaponry and with guns, and they (students) feel safe."
This article originially appeared on the Daily Telegraph.
