America will do whatever is the most expensive option possible. That's why they have wars. To pacify the industrial military complex. Actually going into a place and winning a war in a week is no use at all. Expensive airstrikes over several months, support, setting up military cities, medical supplies, food supplies ... that's what the US is about.
So this suits them. Poke ISIS for as long as possible using the most expensive hardward possible in the most inefficient way possible, means plenty of tax payer money wasted and massive amounts of debt generated. Oh, and absolutely don't wipe out the enemy. Its important they can regroup, rebrand and rejihad again somewhere else.
Britain will want a piece of this too. However the British public are kind of up to speed. We know war is a racket and we largely have stopped giving a hoot about arabs killing each other, despite our media doing its best to show as many injured children as it possibly can. I think the British will try to get in on the action, but there is no way we will before our general election on 7th May 2015 as it would be suicide for the Conservatives.