Senate Republican Leader Mitch McConnell got his first big challenge from the right Wednesday, as the conservative group ForAmerica launched an ad questioning whether the Kentucky Republican is a true conservative.

McConnell, the leader of the Senate’s 45 Republicans, is up for re-election next year. He negotiated a deal with Vice President Joe Biden last week to avoid the fiscal cliff. The package included tax increases on the wealthy and delayed automatic spending cuts two months.

“As negotiations over the so-called fiscal cliff were intensifying,” the ad says, “conservatives called on McConnell and congressional Republicans to hold the line on tax rates and demand cuts to spending as they had promised.”

Instead, ForAmerica says, “when the deadline was looming, McConnell called Vice President Joe Biden and signed off on a deal with the White House that included tax increases and virtually no spending cuts.”

So the group is urging people to sign a petition “to let McConnell and congressional Republicans know conservatives are watching and will hold accountable those who go against the principles they claim to support.”

No candidate is mentioned.

However, ForAmerica’s own “Freedom Meter” gives McConnell a 95 percent rating. The meter claims to measure a lawmaker’s willingness to approve “policies that promote individual freedom” or oppose “legislation in Congress that could hurt American liberty.”

Despite his conservative record, McConnell is well aware that Tea Party conservatives can show strength in Kentucky.

While no major Democrat has stepped forward to challenge McConnell, in 2010 the more conservative Rand Paul beat then-Secretary of State Trey Grayson, McConnell’s handpicked choice for the state’s other Senate seat, in the GOP primary.

In a November interview with McClatchy, McConnell said 2014 wasn’t foremost on his mind. “I don’t want to be overly confident here. I don’t own my seat,” he said. “My only concern right now is not what might happen in 2014 but what might happen in the next three or four weeks.”

Also, McConnell has embraced Paul, even hiring Jesse Benton to run his 2014 re-election effort. Benton ran Paul’s 2010 general election campaign and the 2012 presidential campaign of Paul’s father, U.S. Rep. Ron Paul, R-Texas.