Pryor is, according to an announcement issued by SCF Executive Director Matt Hoskins, the group's top target in 2014.

An SCF source indicated both his vulnerability — Pryor is running for reelection in a state that President Obama lost by more than 20 percentage points in 2012 — and interest from grassroots members in his defeat encouraged the group to set him in its crosshairs as a top target this cycle.

The radio ad, which is backed by $35,000, according to an SCF source, is part of an extended educational campaign that will amount to "10 times that or more" to educate voters on Pryor's record.

It features a man and a woman discussing whether a couple could agree "95 percent of the time," and noting that Pryor "voted with Barack ObamaBarack Hussein ObamaNew Hampshire Rep. Kuster endorses Buttigieg Overnight Defense: Foreign policy takes center stage at Democratic debate | House delivers impeachment articles to Senate | Dems vow to force new vote on Trump's border wall Ray LaHood backs Biden for president MORE 95 percent of the time."

The ad highlights his votes for the stimulus, for Obama's healthcare overhaul, the Wall Street bailout, and charges that he "voted to use taxpayer money to fund Planned Parenthood, the nation's largest provider of abortions."

And it directs listeners to, where supporters can sign up to receive more information. SCF is hoping to build a "massive" email list of supporters from the email to keep active throughout the race, according to an SCF source.

It's an early look at what's likely to be the roadmap for any Republican running to defeat Pryor in an increasingly red state. Though he ran without Republican opposition in 2008, Pryor will face heavy attacks this cycle from groups like the Senate Conservatives Fund and the Club for Growth, which also targeted him with its first ad of the cycle in late February.

No Republican has yet announced an interest in the seat, but Rep. Tom CottonThomas (Tom) Bryant CottonHillicon Valley: Lawmakers say Facebook deepfake ban falls short | House passes bills to win 5G race | Feds sound alarm on cyberthreat from Iran | Ivanka Trump appearance at tech show sparks backlash Cotton introduces bill blocking intel sharing with countries relying on Huawei for 5G GOP senators introduce resolution to change rules, dismiss impeachment without articles MORE (R-Ark.), who is considering a bid, would be likely to get the support of the two groups, which are known for backing anti-establishment candidates.