As of Tuesday afternoon, outside groups had spent nearly $6.2 million to influence the outcome of the race between freshman Republican U.S. Rep. Chip Cravaack and Democrat Rick Nolan in Minnesota's Eighth Congressional district.

Of that, $5.5 million, or nearly 90 percent of it, has been spent to oppose one of the two candidates, largely on attack ads, according to federal records.

Cravaack has been the hardest hit. Groups, from the DCCC to AFSCME, have spent $3.2 million to oppose him while $2.4 million has gone to oppose Nolan.

But Nolan's friends haven't done much to build him up – his supporters, have spent only $360,000 to promote him. Much of that money was spent by the DFL.

Cravaack's supporters have been similarly chintzy in spending cash to boost him. Only about $117,000 has been spent to sing his praises, according to campaign records.