I don't buy it.
First, because straight-line voting is so common.
Second, because, empirically, campaign funding (when both sides have any meaningful sum) has little to no correlation with victory in swing-states or areas with roughly equal party registration.
Third, voter turnout is very low in the US, especially among uneducated people. The average American is very politically uneducated. But the average American voter (not potential voter, but actual voter) is significantly better educated than the average American. Some, even many, may be greatly swayed by simple recognition, especially in low-level elections for county and state offices. But I think most, especially for national offices, make decisions based on bounded understandings of policy, largely gotten by word of mouth and ads. Racial allegiance, religious influence, family history... are all much bigger influences than campaign funding.
Fourth, campaign funding (or threats of funding the foe) DOES have an influence on post-election legislative choices by congressmen: which seems most easily limited, not by complex and easily circumventable campaign finance rules, but by longer, staggered terms and reducing incentives for rent-seeking.
I'm too busy right now to go fetch the numbers, but if you can find them, I'd be more than happy to crunch some numbers and see what the correlation looks like. Obviously, though, a large sample is needed, taking just the last 2 or 3 won't count.
As for the average voter, sure, he's better educated than the average American. That doesn't make him very educated regardless. While I do observe greater radicalism among young and/or poorly educated voters, I have never (anectdotally) observed a significant difference among the educated people when it comes to political awareness. It's not because people have a master's that they care about politics, and even if they do, that doesn't mean they are ready to read the 60+ page programs the parties published at the last federal election.
You speak of things like "racial allegiance", but I'm sure other black people tried to run for leadership of their party before Obama did without anywhere near the support Obama got from their community. Religious influence... You mean, like those religious nuts that are *always* on TV? Whatever trait or agenda a politician has, it cannot influence people unless it is advertised, be it positively by the candidate himself or negatively by his opponents.
As for reducing incentives for rent-seeking, most of these measures I hear of are worse than the corruption their absence could generate.
