May hurt and helped by Juncker clash
The briefing and leaking by a senior Brussels official that last Wednesday's dinner between Juncker and May was a car crash is both good and bad for the Tory leader and prime minister.
It's good because she and her colleagues will ruthlessly exploit the political manoeuvring by a senior aide to the EU Commission's president as proof of how dirty and difficult the Brexit talks will be - and therefore will use it as one of their arguments for why she needs to win big in the looming general election to provide her with great stability at home.
It's not that a big Tory majority would intimidate Juncker and his partner Tusk, it's that it would help her to know she can count on the support of parliament when fighting her corner. Or so she believes.
But what's potentially damaging for May and her Brexit-tasked officials from the FAZ disclosures is the implication that they were ill-prepared, wrong-footed and naive.
Let's just take one important issue - the rights of EU citizens living here, and British citizens living in other EU states.
While many will say it is highly commendable that May wants this settled shortly after the election in June, she knew - or at least should have done - that the German government regards migrants' future status as a highly complicated technical question, partly because of the implications for welfare and health spending, and would never be rushed into a deal.
So it is all very well for UK government sources to fight a rearguard action this morning in the Telegraph, pointing out that when May also asked Tusk for an early deal on migrants' rights a few weeks ago he did not push back, all they are revealing is their worrying ignorance about the ruthlessness and sophistication of their EU counterparts.
And the same critique can be made of Britain's attempt to link the magnitude of our severance payment or divorce bill to the scope and generosity of a future free-trade deal that we seek: keeping these separate is an article of faith for Juncker, Tusk and Merkel; and even May's formidable negotiating powers are highly unlikely to move them.
So here is why that fateful Juncker dinner last week was bad as well as good for her electoral prospects.
It is all very well for her to ask for a strong mandate from us so that she can face down those tricky Brussels so-and-sos.
But if her negotiating approach seems likely to fail, if it increases the likelihood of the UK crashing out of the EU in a chaotic way with no deal, many British people - especially the 48% who voted to remain - will think twice about endorsing her.