Bw - No, she can't. The Monarch's "power" these days amounts to the rather vague "right to be consulted / to warn". In practice, that has meant nothing for a century, more or less. The monarch is a figurehead to whom no PM would pay more than polite attention if they wanted to do something any monarch disapproved of.

It's still a better bet, frankly, than having some random twat (especially some random political, supposedly ex-political, or celebrity twat) "elected" to be Head of State. If you're determined to abolish the monarchy, then just make the PM the HoS. I've never understood the point either of having an elected powerless HoS or of a second HoS that isn't powerless. For all practical purposes the UK PM is the UK HoS; President + PM just seems to muddy the waters.

As for the loathsome republicans amongst you {big wink}, there's no point in me saying anything. The arguments have been hashed, rehashed, recycled, fermented, drunk, pissed out, manured, matured, fermented again and etc so many times... You don't believe 'em, and the rest of us won't agree with you. So why bother? ;-)