Can the Cabinet's EU truce hold?
While David Cameron's officials have been frantically negotiating the draft terms of a deal with the rest of the EU, his Cabinet colleagues, those who favour exit at least, have patiently been keeping their counsel.
Last month after all, they were instructed by Number 10 that it wouldn't be appropriate to get stuck into the arguments before the deal was actually done and the government had taken its final position.
But now the prime minister has been extolling the virtues of what's been achieved without that final agreement, can that truce hold?
One senior government minister told me tonight "the 'deal' is a mess" - and I understand there is debate behind closed doors over whether those who favour exit should stick to the previous deal and keep quiet until the middle of the month or gingerly begin to make the case for exit.
There will be relief in Number 10 tonight that the home secretary has signalled strongly that she will back the PM. But she is not the only one with reservations about the EU.
And while she broke her silence to state qualified support, others may, in the coming days, speak out to say something very different indeed.