It's no secret that outside conservative groups have been extremely active this campaign season. This despite demonizing by Democrats (whose own outside groups are also spending tens of millions of dollars) of so called "anonymous" groups giving cash to Republicans.

But this last 8 days of the campaign will mean the difference between a 45-50 seat gain in the House or something truly astonishing; a win of up to 70 or more House seats.

The key will be targeting those few races that are left where the GOP challenger to a Dem incumbent could use an infusion of cash to put them over the top. These are races where polling tells the pros that the people are ready to boot the Democrat but don't know enough about the GOP challenger to take that final step and vote for them.

This is where the outside groups like American Action Network come in. Coordinated by the Karl Rove created group American Crossroads, an avalanche of badly need cash is set to flow into these races during the final week, largely from these conservative networks:

Working from color-coded master spreadsheets - one of which was obtained by The New York Times - the conservative groups are now closely monitoring polling in 80 House races that they judge crucial to ensuring a Republican majority. Based on those results, the groups have started to place their final advertising bets in ways carefully coordinated to fill openings left by the more financially limited official party and candidate committees.

In several cases, officials with the outside groups said, they intend to force Democrats to spend money in districts they presumed safe; in others, they said they would wipe out financial advantages Democratic incumbents were counting on to stave off strong challenges from underfinanced opponents.

"We're going to continue to have a very strong presence on the Senate and in each of the key House races where we've played a big role," said Steven Law, the president of American Crossroads and Crossroads GPS.

Will all this spending offset the Democratic advantage with labor unions? For once, it appears conservatives have gotten the drop on unions and may match expenditures. Whether it will lead to the kind of history making change in Washington the polls suggest is another question that won't be decided until election day.