Independent Greg Orman, the pro-choice Kansas U.S. Senate candidate, could well unseat anti-choice Republican Sen. Pat Roberts next Tuesday and threaten Republicans’ chances to take over the Senate.

Orman hasn’t decided yet whether he would caucus with Democrats or Republicans, but some conservatives unwilling to take that chance are now lining up behind Roberts after battling the long-time incumbent through much of the past year.

The Tea Party Patriots, which spent more than $75,000 against Roberts in the primary campaign, has now officially endorsed him.

And the political action committee of Tea Party favorite Sen. Rand Paul (R-KY) has come out with a new six-figure ad buy on Roberts’ behalf.

The RAND PAC ad focuses on foreign policy, lauding Roberts for not sending money to “countries that hate us.”

That’s a reference to Roberts supporting Paul’s 2012 proposal, made in the wake of the attack on the U.S. Embassy in Benghazi, Libya, to cut off U.S. aid and loan forgiveness to Egypt, Libya, Pakistan, and any other country with attacks on U.S. diplomatic facilities.

Paul’s support for Roberts, and for Thom Tillis in North Carolina, may be a GOP strategy to woo libertarian voters. Both states have Libertarian Party candidates on the ballot who could draw a crucial few percentage points away from the Republican candidates, so getting a libertarian hero like Paul to campaign for the Republican could be important.

Supporting Roberts is a capitulation to the “establishment” for both the Tea Party Patriots and for Paul, but it’s a move that could affect the balance of pro- and anti-choice voices in the U.S. Senate.

In a recent debate, Orman said unequivocally that he is pro-choice, while Roberts said that considering abortion rights settled law was “unconscionable.”

Orman had been leading in the polls since September, but recent polling shows him having lost significant ground. The race is a toss-up.