Crossroads GPS Releases New Ad Attacking Obama's Fiscal Cliff Offer (VIDEO)

Crossroads GPS, a nonprofit organization founded by conservative strategist Karl Rove, has bought its first television ad since the election, attacking President Barack Obama over his proposed plan to raise the marginal tax rates on the nation's highest earners.

The $500,000 ad buy is set to hit airwaves on national cable networks Thursday, as the negotiations over the so-called fiscal cliff come down to the wire.

Entitled "Over," the ad criticizes the president for focusing the fight on tax hikes and accuses him of neglecting to recommend any serious spending cuts.

"So far a big tax increase is his solution," the narrator intones. "No real spending reforms. Instead more taxes. The time for politics has ended. We need bipartisan ideas we can all support."

Obama released his first offer to congressional Republicans last week, detailing $1.6 trillion in new revenues over the course of the next decade. The bulk of new revenues will come from letting the marginal tax rates on the top 2 percent of earners return to Clinton-era rates, but $600 billion is slated to accumulate through capping itemized deductions for the wealthy and other taxes.

In addition to the new revenues, Obama also called for an extension of the payroll tax cut, $50 billion in additional stimulus and up to $400 billion in cuts to entitlement programs over the next decade.

Republicans greeted the president's offer -- at least publicly -- with disbelief . House Speaker John Boehner (R-Ohio) has in turn indicated that he would be willing to accept as much as $800 billion in new revenues over the next 10 years from closing loopholes and eliminating deductions.

The White House has shown it is not serious about the debt, as it has yet to propose significant spending cuts to go along with its massive proposed tax hikes," Crossroads GPS President and CEO Steven Law said in a statement regarding the group's ad buy. "Serious revenue concessions have been made, but Obama won't take yes for an answer."

As a 510 (c)(4) organization, Crossroads GPS is not legally required to disclose its donors. Although the group brands itself as one focused on "grassroots policy strategies," it has funded its past activities through $10 million checks . Now the group is spending its dark money to influence the debate over deficit reduction.

"Every day wasted is another $4 billion we're deeper in debt," the ad concludes.