Foreign affairs are definitely important. Allowing foreign money to fund elections however, is a terrible idea. Since foreign investors cannot vote in our election, they should not be provided any opportunity to sway our elections. Foreign funding in our elections will just lead to abuse of political power once a candidate is in office.
Allowing an outside nation to find a domestic election would be similar to allowing a corporation outside of a town to find that town's mayoral or school board race. It is possible that the outside funding agency could have some stake in which way the election goes, and that their very presence as funders might sway voters and campaigners one way or another. It is best for elections to be decided within communities. Since money plays a huge role in elections, it is best if the funding comes only fro the nation involved.