Senate Republicans are poised to filibuster President Obama’s nominee for director of the Federal Housing Finance Authority, Rep. Mel Watt (D-N.C.). (Jacquelyn Martin/AP)

The Senate resumed its never-ending war over confirmations this week, as a pair of President Obama’s key nominees appeared headed for white-knuckle votes in the face of a GOP blockade.

With votes slated for Thursday, Senate Republicans were poised to reject by filibuster the nomination of Rep. Mel Watt (D-N.C.) to head a major federal housing agency. Patricia Millett’s bid for a seat on the prestigious D.C. Circuit Court of Appeals also looked to be right on the margin of getting the 60 votes needed defeat a filibuster.

The two standoffs come as a group of other Republicans, led by Sens. Lindsey O. Graham (R-S.C.) and John McCain (R-Ariz.), have threatened to filibuster the nominations of Janet L. Yellen for Federal Reserve chairman, Jeh Johnson for homeland security secretary and a host of otherpresidential picks.

In most cases, the GOP objections are not based on the merit of the nominee in question, but rather attempts by the Senate minority to fight unrelated procedural battles.

Watt’s nomination to run the Federal Housing Finance Agency, which oversees mortgage giants Fannie Mae and Freddie Mac, ­faces the greatest peril. A number of Republicans said in recent days that Watt — a senior member of the House Financial Services Committee — does not have the requisite experience to oversee such a massive agency.

“He is a good man up for the wrong job,” Sen. Lamar Alexander (R-Tenn.) said.

“I get the impression that the nomination is in difficulty,” McCain said.

Both senior GOP senators said they were also opposed to Millet’s nomination to a lifetime appointment on the D.C. Circuit bench, which many legal experts view as the second most important court in the nation. Sen. Kelly Ayotte (R-N.H.), who has worked with McCain and Alexander on bipartisan deals in recent months, also said she would oppose Watt and Millet.

Their objections are an important bellwether because all three have been pivotal in helping defuse recent tensions over nominations. In July, McCain and Alexander helped negotiate a deal with Majority Leader Harry M. Reid (D-Nev.) to avoid changing Senate rules over GOP filibusters of nominees to low-profile boards and commissions.

That agreement was on display this week as the Senate quickly confirmed a handful of nominees to posts including National Labor Relations Board counsel, an undersecretary at the Pentagon and the new director of the Office of Personnel Management.

But if Democrats see both Watt and Millet rejected by GOP filibusters Thursday, it might set the stage for another fight over Senate rules.

At a rally in support of Millet’s nomination Tuesday, Sen. Patrick J. Leahy (D-Vt.), chairman of the Judiciary Committee, said a filibuster of her would create “almost insurmountable” pressure from liberals to change the rules to allow certain nominations to be approved on a simple majority vote.

Republicans have acknowledged that they do not object to Millet’s credentials — she is an accomplished appellate court lawyer who has argued 32 cases before the Supreme Court — but object to Democratic appointees on the important D.C. federal court. “This vote has nothing to do with this nominee,” Alexander said.

The eight current members of the appellate court are evenly divided between judges nominated by Republican and Democratic administrations. There are three vacancies, including the seat that Millett has been nominated to fill, but Republicans say that the court’s caseload is not heavy enough to warrant appointments ahead of other circuits.

Sen. Charles E. Grassley (R-
Iowa), ranking member of the Judiciary Committee, has legislation that would reduce the size of the D.C. Circuit Court, and some Republicans said they would be willing to consider supporting Millett’s nomination after a broader negotiation over the size of each circuit court.

Graham said that after this current crop of confirmation battles, he intends to place a “hold” on every other nominee until Congress is permitted to interview more witnesses about the Sept. 11, 2012, attack on the U.S. consulate in Benghazi.

“How can you close a case when don’t talk to the witnesses?” Graham asked reporters Wednesday.

Graham said the move would apply to the Yellen nomination to run the Fed.

In Senate custom, a hold is essentially a preemptive notice by a senator that they would likely filibuster a nominee or legislation, but it can be overcome with 60 votes.