If a state actor wanted to really f**k up another country.

What would they do?

Support an unqualified, boorish, bigoted ass for that country's highest office. Check.
Vilify and spread untruths about the boor's opponent. Check.
Note an anachronism in that country's electoral system that could put the boor in office with a minority of the votes. ?
Provide the boor with the fictitious votes he needed to exploit the anachronism. ?
Leave enough traces of what they had done so smart people would realize the election results were bogus. ?
Sit back, enjoy and take advantage of the chaos. ?

I have been thinking, if an election was ever designed to wreck this country, it would look like this.  I find it hard to believe even the Russians want a loose cannon like Drumpf holding the nuclear football.  If obvious vote tampering is found, the plan for chaos will be complete.