Trump predictably defended his recent steel tariffs for the Pittsburgh audience, saying that he has received phone calls from countries hoping to avoid sanctions.
It was not the first time Trump had suggested executing drug dealers.
During the campaign event in Pittsburgh, the president also veered off into a list of other topics, including North Korea, his distaste for the news media and his own election victory 16 months ago. "He's going to vote the party line".
Under pressure over a scandal involving a porn star named Stormy Daniels, Mr Trump singled out his wife, Melania, for praise.
"I'd love Oprah to win, I'd beat Oprah".
US President Donald Trump has stressed the significance of his plan to impose heavy tariffs on steel and aluminum imports.
"We have to build a wall", Trump said. "I don't know if we're ready - I don't know if this country's ready for it", Trump said. All this is Trump fulfilling his desperate and personal need to both entertain and be loved even if it comes at the expense of the GOP candidate he was there to endorse.
The rally was in support of Republican Rick Saccone, who in the final days of a close special congressional election in a district with an estimated 17,000 steelworkers. A survey of voters shows 4% of black women and 25% of Hispanic women supported Trump. "Rick is going to vote for us all the time, all the time".
Trump said the only way to solve the nation's drug problem is through toughness.
"Steel is back", he proclaimed a few times.
TRUMP: We need our Congressman Saccone.
Before the speech, White House officials said Mr. Trump would focus much of his time framing his new steel and aluminum tariffs as a boon to workers in steel-producing regions such as western Pennsylvania. His message, if voters hear it, is focused on his support for Trump, his experience in the public and private sector, his opposition to abortion rights, and efforts to link his opponent to the top Democrat in the U.S. House, California's Nancy Pelosi.
Trump regaled his audience with meetings alongside world leaders. "I know her very, very well", Trump said, without elaborating what that weakness could be.
He called Mr. Saccone "a really good person" and invited the candidate on stage during the rally.
Republicans say Democrats are benefiting from an "A+ candidate", whereas they have a lackluster option, who's struggled to raise money.
Trump has also announced the slogan for his 2020 presidential re-election campaign - 'Keep America Great!'
Saccone is in an unusually tight race against Democratic candidate Conor Lamb, a former Marine and federal prosecutor who's never run for office before, for Pennsylvania's 18th congressional district.
Trump also reprised his criticism of liberal Senator Elizabeth Warren, whom he mocks as "Pocahantas", and Senator Bernie Sanders, the far left independent who challenged Hillary Clinton for the Democratic nomination in 2016.
"[South Korean President Moon Jae-in] said without Donald Trump, the Olympics would have been a failure", Trump said. Senate race in Alabama, although the president did not make those men the centerpiece of his comments.