Republican wave?

They are encouraged by what they're seeing in the home stretch of the House campaign. | Getty

By ALEX ISENSTADT | 10/17/2014 05:05 AM EDT | Updated: 10/18/2014 03:59 PM EDT

Republicans are taking their most aggressive steps yet to parlay a favorable national climate and growing cash advantage into a historic House majority.

Aiming to stretch the political map, two prominent conservative groups, American Action Network and Congressional Leadership Fund, on Friday will announce a joint $3 million investment in seven House races, including contests in deep blue districts that are just now starting to be seen as realistic targets for Republicans.

They're not saying it's a wave, at least not yet. But Republicans are encouraged by what they're seeing in the homestretch of the House campaign and are determined not to let an opportunity pass.

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The coming offensive will reach as far as President Barack Obama's home state of Hawaii, where recent polling in one district has shown Republicans to be surprisingly competitive. It will also take them to a liberal northeastern Iowa seat where Democrats are suddenly on defense, and to an upstate New York district not long ago seen as safe for the president's party. Obama carried each district in 2012, in most cases handily; in the Hawaii district, he won 70 percent of the vote.

Republicans, who currently hold a 17-seat majority, are driving deep onto enemy turf just as Democrats have gone on the retreat. A late cash infusion from GOP-aligned groups has forced Democrats to pull resources from top offensive targets in order to buttress besieged incumbents, putting them almost entirely on defense. Of the 28 races seen as most seriously in contention, all but seven are held by Democrats.

Republicans are now responding by putting more Democrats on guard. GOP groups have been poring over polling data in all three districts but have yet to make a serious investment in them. With Friday's announcement, that changes.

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"After wasting millions and abandoning prized candidates, House Democrats are now retreating at a breakneck pace. This latest investment speaks volumes about the quality of our candidates and the expanding opportunities for House Republicans in deep Democrat territory," said Dan Conston, a spokesman for American Action Network and Congressional Leadership Fund.

The maneuvering could alter the conventional wisdom surrounding this year's House races: that Republicans are on their way to a respectable single-digit gain in the House but are likely to fall short of a double-digit pickup that would give them their biggest majority since Harry Truman's presidency. Confining the GOP is a small congressional map that left few incumbents from either party in serious jeopardy; only about 30 seats, give or take, have been seen as truly in play.

Republicans believe if they can maximize their House margin in 2014, it will give them a buffer going into a 2016 election expected to be much more favorable to Democrats.