Hello from Austria.

My question is regarding the presidential nominee thingy, because as an Austrian, I don't really understand the system.

I got the whole thing with Republicans vs. Democrats, but what exactly is happening the last few months.

Possible candidates are touring the US. to gain sympathy from the voters, but they are running for a party.

As far as I know, Donald Trump is leading those polls for the Republican party, but is the Republican party forced to choose him as their final presidental candidate? Or do they have to choice to choose anyone, no matter what the polls are.

Trump has roughly about 40% nationwide of those republican votes at the moment(according to his own polls), but if the Republican party says: This guy is not our official presidental candidate because of reason XY, AND Trump says: I'll be a non party presidential candidate then, aren't the Republicans in trouble, because they will lose a huge amount of votes?

Is my thinking right here, that if the Republican party does not select Trump as their official candidate, they lose a huge amount of votes and lose the entire presidental thingy, and if they choose him, well they chose Donald Trump as their official candidate, which is something.

I don't get the whole system, its so unneccesary complicated compared to european elections.

Hope somebody can help.

Thanks