My concern over May sending in troops is that there would no longer be even a pretence at neutraliy,
just imposing hardline Unionist views on the Catholic population and rolling back the rights obtained from the GFA
Corbyn is not controlled by the DUP, so I would expect him to work with the RoI,
especially considering that almost half the voters are Catholic and a majority of the young.
The whole NI border problem is a result of the colonisers - England / Britain - refusing to accept a democratic vote by the whole of Ireland to become independent.
Britain partitioned Ireland under threat of a brutal scorched earth war.
If Britain had just accepted democracy then, the NI border wouldn't exist to be a roadblock now.
However, even without NI, one problem would still remain:
Brexiters - including the UK govt - want to Brexit, but keep all the bits they need from the EU
The Tory party wouldn't be tearing itself apart if they thought Brexit was beneficial or even neutral for the country:
They are in total panic because they realise it will be a longterm disaster
Those few MPs not panicking are either ignoramuses or clever folk ecpecting to make big profits by hedging against Sterling and British companies.
The EU is not stopping the UK from Leaving, just not allowing them to dismantle the SIngle Market and loot the bits they want.