Should national level groups be involved in state level elections?

OK, this happens across the political spectrum, so hopefully we can keep ideology to a minimum. I heard a story this morning about a congressional race in New York in which a third party conservative was leading the republican. It was supposed to be about the future of the Republican Party, but I thought what was more interesting were the adds from national groups for the third party candidate, for the republican candidate, and for the democratic candidate.

Seems to me that national involvement used to be mainly from the party, and mostly about gaining a seat. With this race, and with the race for Joe Lieberman’s Senate seat, we have outside groups who just want one ideological vote instead of trying to gain control of the body.

If opponents of campaign finance are right that money is part of having your say in a democratic election, and if congresspeople have a role in representing specific geographically based interests, then is this kind of national funding subverting democracy? Is it making congresspeople represent an ideology over an area?