Article 5 of the Nato charter mandates that member nations come to the defence of allies if one is attacked.
Earlier this week, the Post reported that the Trump campaign had played an active role in softening language on the American commitment to Ukraine (a non-Nato member that has tried to join), which is still locked in a tense situation with Russia. Trump's campaign manager, Paul Manafort, once worked as a lobbyist for the Russian-backed president of Ukraine who was ousted in 2014.
Trump's antipathy to Nato isn't new. Earlier this year he suggested that the US role should be scaled back.
Turkey, a Nato member, got particular attention in the interview. Pence referred to the attempted coup in Turkey as evidence of "a world spinning apart". When the New York Times asked Trump if he would demand that Turkey not violate the civil liberties of its citizens Trump said: "I don't think we have a right to lecture. Look at what is happening in our country. How are we going to lecture when people are shooting policemen in cold blood?"
The feud that never ended
Anybody hoping for a moment of healing and unification in the GOP when Ted Cruz took the stage is now sorely disappointed. It got ugly.
In the hours before the speech, a report suggested that Cruz would challenge Donald Trump in a primary in 2020 even if Trump wins the presidency. Cruz notably didn't endorse his party's nominee in his speech, offering only congratulations.
Later, he said: "And, to those listening, please don't stay home in November. If you love our country and love our children as much as you do, stand and speak and vote your conscience. Vote for candidates up and down the ticket who you trust to defend our freedom, and to be faithful to the Constitution."
Trump's own conduct during the speech was highly questionable. He arrived at the convention hall as Cruz was getting started, and numerous TV channels cut to Trump walking in. By the end, with the crowd chanting that Cruz should endorse Trump, the nominee waved to the crowd and gave a thumbs-up.
And it should be no surprise. There were seriously hard feelings during and after the GOP primary. Trump insulted the appearance of Cruz's wife, threatened to "spill the beans" on her and even referenced a tabloid report that Cruz's father might have been involved in the Kennedy assassination. Cruz labelled Trump a "snivelling coward". Perhaps Cruz never really got over it.
He was given a slot in prime time at the convention despite not promising to endorse Trump. Other speakers have endorsed Trump in various ways but declined to say much about him; Cruz wouldn't even go that far. Cruz's speech was a stunning bit of political theater and threatens to be a definitive one.