The mid-terms in the USA will be (another) testbed for the proposition that you can *just* buy the result of democracy... Republicans have built up a warchest of nearly $1bn around double what the Democrats have available to spend.
However, currently polls are favouring the Democrats, so the Q. is whether the Republicans' spend can reverse that polling advantage.
And of course there's always the chance of *actual* electoral interference from the White House.