Two striking things about today.
Theresa May without hesitation said that she would be willing to press the nuclear button - without flinching in the face of that question, there was not a moment's doubt.
Secondly, how much agony there was on the Labour benches. The party's difficulties around Trident crystallising the divisions and doubts inside the party.
Possibly tomorrow, but possibly not until Wednesday, Labour will know which of its MPs will take on Jeremy Corbyn in a leadership contest over the summer.
Whether it is Owen Smith or Angela Eagle, they both support the nuclear deterrent so that issue will be neutralised for the party if Jeremy Corbyn is defeated.
There will, I understand, be only one of them on the ticket - by the end of play on Wednesday the one with fewer nominations will drop out - sources tell me it is "neck and neck".
But as the Tories get down to business under Theresa May, there are plenty of problems brewing. The opposition has a long way to go, maybe a long hot summer, before they can look like they are in any shape to take them on.