I would certainly not prefer the army to an elected body, chosen by the respective constituencies. It seems likely that there will be a general election, and people will stand on whatever their manifesto is at the time. I think that the fact the members of parliament voted on support of article 50 meant they voted to leave, but I don't think it means they voted "leave at any price." If the price is, in their judgement, too high, they have not only the right but the duty to say so, and if need be pay the price at the next election.