Even Ted Cruz thinks there should be full and immediate disclosure: https://www.youtube.com/watch?v=vrmUvAoPV1I&feature=youtu.be
And if Russia or China was participating to a significant degree in our internal politics, that would come out as a national security issue and should be dealt with in other ways.
I know that my position isn't popular, but the Federalist papers talked about this issue, and took the position that for every David Koch there is a Tom Steyer. Why not let them waste all of their money fighting each other? There are several recent examples illustrating that money doesn't buy elections. Maybe it's not a fact yet, but there's enough evidence behind it that I think it's a defensible position.
If this takes off, I think the end result will be less participation in the political process by average Americans, who fear retaliation down the road. Maybe it looks like a difficult balance to you, but I think I would always come down on the side of more speech rather than less.
I'd rather have small donors have a bigger share of voice.
We know Russia has done this successfully at least once.
According to Time magazine, a US State Department official estimated that the KGB may have spent $600 million on the peace offensive up to 1983, channeling funds through national Communist parties or the World Peace Council "to a host of new antiwar organizations that would, in many cases, reject the financial help if they knew the source."[13] Richard Felix Staar in his book Foreign Policies of the Soviet Union says that non-communist peace movements without overt ties to the USSR were "virtually controlled" by it. Lord Chalfont claimed that the Soviet Union was giving the European peace movement £100 million a year. The Federation of Conservative Students (FCS) alleged Soviet funding of CND.
http://en.wikipedia.org/wiki/Soviet_influence_on_the_peace_m...
I would be surprised if governments weren't still attempting to influence each others' internal politics.