you were probably busy and didn't see this:
Under federal law and Federal Election Commission regulations, both foreign nationals and foreign governments are prohibited from making contributions or spending money to influence a federal, state or local election in the United States. The ban includes independent expenditures made in connection with an election.
Those banned from such spending include foreign citizens, foreign governments, foreign political parties, foreign corporations, foreign associations and foreign partnerships, according to the FEC. (Permanent residents who hold green cards, however, are not considered foreign nationals.) Violators face civil penalties, as well as criminal prosecution if they are found to have knowingly broken the law.
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part b)
Yes Russia has tried but succeeded this time. The question is, did they have American citizens collude to advance their cause.
As far as Americans doing same ---- to quote many (R), "that is troubling"
Putn would not have helped HRC --- so your hypothetical is irrelevant from git -go.
The reasons for choosing Trump over HRC are documented and you can look them up