The PM is caught in the perfect storm, the situation is thus:
1) If Clinton had won the US election, a UK-US trade deal would’ve been far easier to sell to the electorate. Unfortunately, a divisive demagogue with a history of reneging on trade deals won instead.
2) Europe is THE most divisive issue within the Conservative Party. A hard Brexit would be a horrific scenario for three-quarters of Tory MPs. A significant amount of contributions to the party come from businesses and farmers, who stand to significantly lose out in event of a WTO Brexit.
3) Appeasing the Hard Brexiteers is likely to lose the Conservatives the next election and probably the one after that. The party is in a mess, having taken only seven years to plunge into dysfunction and even a partisan media won’t be enough to save them.
4) Labour have understandably stood back from the sidelines and watched the shitshow unfold, knowing that the last thing they actually want is to be handed a poisoned chalice, which is exactly what will happen if the government collapses. They appear to be adhering to the text of the referendum ballot, which stipulated Single Market access.
5) If Theresa May backs away from a Hard Brexit, the issue of Europe will continue to haunt the Conservative Party with a probable damaging euro-sceptic rebellion further down the line.
6) It is only a matter of time before someone leaks those heavily redacted impact assessment reports. No-one (yet) outside of the various select committees have seen them, but suffice it is to say that they are sufficiently damaging to ensure that MPs obfuscated over their release.
7) No-one in their right mind wants to be a Conservative Prime Minister right now. The leadership challengers are waiting in the wings because their most optimistic move to grab power would be on the back of a general election loss and subsequent term of parliament rebuilding the party in opposition.
8) Ireland. Either allow NI regulatory alignment with Eire, or the resulting hard border between the two regions crosses a line for both Dublin and the DUP. Such a move could potentially plunge Northern Ireland into unrest, which could not easily be blamed on the actions of a few extremists.