Donald Trump praised Vladimir Putin on Wednesday for his high approval ratings and his "very strong control" over Russia, comparing him favourably to Barack Obama, the US president.
Mr Trump made the comments during a foreign policy forum in which Hillary Clinton appeared first and had difficulty answering questions about her handling of classified materials as secretary of state.
The Republican nominee then took the stage, and presented several unorthodox prescriptions for America's approach to foreign affairs.
"The man has very strong control over a country," Mr Trump said of Mr Putin at one point. "It's a very different system and I don't happen to like the system, but certainly, in that system, he's been a leader, far more than our president has been a leader."
Mr Trump repeated his claim that he opposed the invasion of Iraq – despite the fact that he expressed support for it in a 2002 interview – and said that after the US combat mission ended troops should have remained to "take the oil".
"It used to be to the victor belongs the spoils," he told NBC moderator Matt Lauer, contending that if the US had commandeered Iraq's oil supply the Islamic State of Iraq and the Levant (Isil) would not exist.
As for his strategy to defeat Isil, Mr Trump continued to refuse to offer a plan so as to remain unpredictable.
He did say he would meet with senior military leaders after taking office to discuss combating Isil, and would adopt the plan they proposed if he preferred it to his own.
The businessman suggested that he would remove the top military officials who had been advising Barack Obama, however, and usher in a new upper echelon.
"I think under the leadership of Barack Obama and Hillary Clinton the generals have been reduced to rubble," he said.
His assessment of Mr Putin was more positive. Mr Trump said he felt hecould get along with the Russian president, and was glad to have received a compliment from him.
"Well I think when he called me brilliant, I'll take the compliment, okay?" Mr Trump said. "Look, it's not going to get him anywhere. I'm a negotiator."
While Mr Trump's performance may have underlined his inexperience in handling foreign affairs, Mrs Clinton's was far from assured.
Much of her half hour on stage was dominated by the scandal over her emails and her vote in favour of the Iraq War.
Mrs Clinton said she had owned up to "my mistake" of supporting the invasion, and urged Mr Trump to do the same, and pledged that the US would never again send ground troops to Iraq.
There were immediate cries from her supporters that the lines of questioning had been unbalanced, with Mr Trump receiving a less pointed interrogation, but the fact remained that Mrs Clinton appeared to have been knocked off balance.
Actually, that’s just what taking the office of President seriously looks like. twitter.com/Reince/status/…
Reince Priebus, chairman of the Republican National Committee, attempted to seize on Mrs Clinton's apparent stumble.
"Hillary Clinton was angry and defensive the entire time – no smile and uncomfortable upset that she was caught wrongly sending our secrets," he wrote on Twitter.
Minutes later came a response from Mrs Clinton's account: "Actually, that's just what taking the office of president seriously looks like"