The Republican National Committee unveiled a slew of new radio ads Tuesday targeting vulnerable Democratic senators and Senate hopefuls on Obamacare -- including in two races where major would-be Republican challengers have yet to join the race.

The ads are set to air in 40 media markets nationwide, including in New Hampshire, where Democratic Sen. Jeanne Shaheen is seeking re-election, and Virginia, where Democratic Sen. Mark Warner is running for a second term. Neither seat had been seriously considered to be in play, but a prominent Republican is now weighing a bid in each race: former Massachusetts Sen. Scott Brown in New Hampshire, and former RNC Chairman Ed Gillespie in Virginia.

Although neither Brown nor Gillespie has publicly announced their candidacy, RNC Chairman Reince Priebus hinted on a conference call with reporters that national Republicans are optimistic both men might. When asked whether the RNC would continue to spend money in long-shot Virginia, Priebus said: "That's a promise. We will be involved in Virginia."

The radio ads, which attack Democrats for echoing the president's broken promise that people would be able to keep any pre-existing health care plan under Obamacare, will also target Democrats in 10 other states, including Louisiana, North Carolina, Alaska, Colorado, Arkansas and Oregon.