Johnson has thrown US ambassador under the bus, say top Tories
Well, your lot selected him for the final 2, knowing he'd almost certainly be PM 
https://www.theguardian.com/uk-news/2019/jul/10/kim-darroch-resigns-as-uk-ambassador-to-us-after-leaked-trump-comment
he concluded he could not go on after he watched Tuesday’s Conservative leadership TV debate,
where Johnson repeatedly dodged questions about whether he would sack the ambassador if he became PM.
.....
A broad political consensus has emerged that Johnson’s refusal to back Darroch had made the diplomat’s position untenable.
Senior Conservative MPs joined the direct criticism of the leadership contender, describing his conduct as “unedifying” and “contemptible”.
Tom Tugendhat, the chair of the foreign affairs select committee, asked:
“If you do not support those you put into very difficult positions, what do you think is going to happen?”
In language that will be viewed as an implicit rebuke of Johnson, Theresa May told MPs:
"I hope the house will reflect on the importance of defending our values and principles, particularly when they are under pressure.”
....
Sir Alan Duncan, a Foreign Office minister, attacked Johnson’s role in the affair.
“For someone who wants to lead, let alone unite, the country, that was contemptible negligence on his part,” Duncan told the BBC.
“He has basically thrown this fantastic diplomat under the bus to serve his own personal interests.”
The Conservative MP Sir Patrick McLoughlin agreed, saying:
“It is unedifying to see someone who wants to be prime minister failing to stand up for hard-working civil servants, who have done nothing wrong, under attack from foreign governments.
Leadership involves standing up for your team.”
...
Jeremy Corbyn called the treatment of Darroch “beyond unfair and wrong” and said he had given “honourable and good service”.