>I'm sure everyone agrees that no country should be allowed to interfere with another countries elections.

Nope.
Some people always mess with other countries elections, and every nation does it to some degree - either by politicians visiting heads of state / politicians, uttering special remarks near elections and so on, causing things to be sent/printed....
Any MI6 type of organization HAS to try to influence elections in target countries as well.

Every country is responsible to find out about such activities and should handle it according to own past meddling - worst of all attitudes is the holier than thou attitude that own meddling is/was [ok, justified,ordained by God].