I think that's broadly right. I set out below quite a useful piece on the Fixed Parliament Act published by BBC news a couple of days ago. Simple or certain, it isn't, but it does support your view that theoretically, it may be a weapon in the hands of the rebels against May. Whether the ERG would vote against May's government on a Corbyn VONC I don't know. It's a dangerous strategy, so I think not. Splits within the Tory Party would never be healed.
The ERG could form some sort of unofficial alliance with the DUP which would emasculate the government and force May to listen to the rebels on the Brexit deal. In practice, she would be mad now, having had this shot across her bow, not to be inclusive of the rebels and the DUP. She begins to sound as if she's persuaded that nothing but a legally enforceable and unilateral termination to the Ireland backstop is acceptable. She must go to the EU and get his. Her leverage? A possible move to WTO instead which would mean the EU would not get the £39bn which they are desperate for. She HAS to use this leverage, and in my view, should have done before now and perhaps we would not have found ourselves in this position.
"Under FTPA, the Commons could remove a government by a simple majority, if it passed a motion in a specified form, and that would start the clock on a 14-day deadline for finding a successor government capable of commanding confidence (motions with different wording would not engage the act).
The prime minister would have to advise the Queen who might be best placed to head a new government, and they would then have to submit themselves to a confidence motion, to show that they could command a majority in the Commons.
If no new government emerged, the Speaker would then sign a certificate, and the Queen would have to dissolve Parliament.
No election needed?
There's a separate process to get a two-thirds majority to hold an early election, so the big change is that the Act ends the ability of the prime minister to simply call an election at a moment of their choice, and decouples the removal of a government from the holding of an election.
This week, the Commons
Public Administration and Constitutional Affairs Committee (PACAC) suggested that MPs would have other options. They argue that any Commons motion which withdrew the confidence of the House from a government should lead to its resignation, because without confidence it would have no right to govern, and in particular no right to levy taxes.
And this is no mere piece of hair-splitting. What it means is that it would - if the PACAC view holds - be possible to oust a government without triggering that 14-day deadline.
So there would be a longer interlude with a caretaker administration keeping the machinery of state ticking over, during which a new government might, or might not, be formed, perhaps with a couple of candidates and party combinations trying their luck.
The difference is that there would be no prospect of Mr Speaker signing that dreaded certificate to dissolve Parliament, so there would not be a rigid time limit. Of course, eventually it might become clear that no government could be formed - and then, perhaps FTPA might kick in, with a motion to dissolve Parliament.
It is not clear that the committee's analysis, though based on a painstaking inquiry with ministers and constitutional experts, redefines the constitutional position. But it might, and if it did, it could matter a great deal.
One of the regular features of the Brexit process has been the way apparent procedural small print like the Grieve Amendment or applicability of the Humble Address procedure has emerged to shape events - and this might provide another such occurrence.
At the moment a successful no confidence motion looks a fairly distant prospect; either the DUP would have to vote alongside Jeremy Corbyn to remove Theresa May, or (perhaps "and") a number of Conservative MPs would have to do so.
Either of these seems unlikely, but the new-look no confidence system does provide the DUP or Tory rebels with the potential excuse that they were voting to remove this prime minister, not the Conservative government.
It would be a fig-leaf, at least.