It's one thing for Democrats or members of the "establishment" to bash Trump in public, however when members of his own party lash out, it may be time to get concerned, even if the person responsible happens to be a know critic of the president.

Breaking with conventional protocol, and failing to deliver the message of reassurance that U.S. officials visiting Germany sought to convey on their debut trip to Europe, republican senator John McCain said on Friday that Trump's administration was in "disarray". McCain told the Munich Security Conference, where earlier in the day Germany defense minister Ursula can der Leyen warned Trump to stop threatening the EU, abandoning Western values and seeking close ties with Russia, that the resignation of the new president's security adviser Michael Flynn over his contacts with Russia reflected deep problems in Washington.

"I think that the Flynn issue obviously is something that shows that in many respects this administration is in disarray and they've got a lot of work to do," said McCain who added that "the president, I think, makes statements (and) on other occasions contradicts himself. So we've learned to watch what the president does as opposed to what he says," he said.

This is the same John McCain who earlier in the week was recorded in a prank phone call, in which two Russian hackers got the bellicore Senator to divulge key aspects of US strategy vis-a-vis Ukraine and Russia.

As discussed earlier, the debut trip to Europe of Trump's Defense Secretary Jim Mattis and Secretary of State Rex Tillerson, to a meeting of G20 counterparts in Bonn, went some way to assuaging concerns as they both took a more traditional U.S. position. But, as Reuters notes, Trump is wrestling with a growing controversy at home about potential ties between his aides and Russia, which he dismissed on Thursday as a "ruse" and "scam" perpetrated by a hostile news media.

And yet, until the sudden and unexpected statement by McCain, things were going smoothly: Mattis made clear to allies, both at NATO in Brussels and in Munich, that the United States would not retreat from leadership as the European continent grapples with an assertive Russia, wars in eastern and southern Mediterranean countries, and attacks by Islamist militants. Mattis told a crowd that included heads of state and more than 70 defense ministers that Trump backed NATO. "President Trump came into office and has thrown now his full support to NATO. He too espouses NATO's need to adapt to today's strategic situation for it to remain credible, capable, and relevant," Mattis said.

Remarks to be delivered by Vice President Mike Pence at the Munich conference on Saturday reveal a similar message of reassurance. Pence will say that Europe is an "indispensable partner" for the United States, a senior White House foreign policy adviser told reporters.

Unfortunately, when a diplomatic mission can not even deliver a united front, it will be for nothing:

The Europeans may need more persuading that Washington stands with it on a range of security issues. "There is still a lot of uncertainty," Sebastian Kurz, Austria's foreign minister, told reporters. "The big topic in Munich is looking to the USA to see which developments to expect next."

If Europeans really want clarity about what to expect next, they may want to look away from the US for the time being.