Senate Republicans block Obama nominees WASHINGTON - Senate Republicans' rejection Thursday of two key nominations by President Obama revived a battle over filibuster rules and opened a new partisan front just as congressional leaders and the White House are searching for a budget compromise to avert another government shutdown. Democrats in the Senate immediately renewed a threat to use their majority to impose the so-called nuclear option, making a historic change to long-standing Senate rules that would prevent a minority party - currently Republicans - from blocking such nominations through filibuster. The latest clash erupted when Republicans blocked two procedural votes on the confirmations of Rep. Melvin Watt (D-N.C.) as top regulator for Fannie Mae and Freddie Mac, and Patricia Millett, Obama's selection to sit on the D.C. District Court of Appeals, considered the nation's most influential after the Supreme Court. The Democratic-controlled Senate voted 55 to 38 in favor of Millett, and 56 to 42 for Watt, but both fell short of the 60 votes needed to overcome a Republican filibuster. Democrats accused Republicans of rejecting highly qualified presidential choices. Watt became the first sitting member of the House to be denied Senate confirmation in 170 years. Members of the Congressional Black Caucus stood silently on the floor during his vote to protest Republicans' blocking of an African American to a senior post. Republicans countered that Watt was not qualified to lead the complex Federal Housing Finance Agency, a job usually filled by a technocrat, not a politician. Opposition to Millett, they said, was not based on her qualifications, but on a concern that the D.C. Circuit Court does not have the workload to justify adding another member. Republicans also complained that they feared Obama was attempting to stack the important court - which frequently rules on federal regulations and is a stepping stone to the Supreme Court - with more liberal judges. Currently, the panel is split evenly between four Democratic and four Republican appointees. The confrontation sets the stage for more bruising partisan battles just weeks after a 16-day government shutdown drove public approval numbers for Congress to record lows. A compromise last month reopened government offices and delayed a potential debt default, but lawmakers must still reach a compromise over taxes and spending before the next shutdown deadline, in January. Most of the shutdown drama focused on the fractious battles in the House, and many in the Senate tried to portray themselves as Congress' only rational actors, crafting the bipartisan compromise that eventually allowed government services to resume. Now the Senate appears headed toward a resumption of its own parochial squabbling over rules. After the vote, Senate Majority Leader Harry Reid (D-Nev.) said he would exercise his right to reconsider the nominations soon. "I hope my Republican colleagues will reconsider their continued run of unprecedented obstructionism," he said. Something has to change, and I hope we can make the changes necessary through cooperation. Vice President Joe Biden, at the Capitol on Thursday to swear in Democrat Cory Booker as the new senator from New Jersey, said it was "time for common sense" on confirmations. Booker's arrival gave Democrats the 55th vote they lost in June when a Republican was appointed to fill the seat of the late Sen. Frank R. Lautenberg until an election could be held. "Mel Watt is absolutely, totally, thoroughly qualified, and it's a gigantic disappointment," Biden said, adding that changing Senate rules was "worth considering." It was only three months ago that senators reached a last-minute deal to preempt the Democratic majority's threat to eliminate the filibuster as a tool to oppose presidential nominations for executive-branch posts. As a result of the accord, Obama's choices to lead the Department of Labor, the Environmental Protection Agency and the Bureau of Alcohol, Tobacco, Firearms and Explosives, as well as a full slate of nominees to the National Labor Relations Board, were installed after prolonged delays. The fragile peace between the parties that followed included not only the deal to reopen the government but also an agreement to lower student loan rates. Hopes that a bipartisan spirit would linger in the Senate were dashed on Monday, however, when called for new votes on the slate of pending appointments. Two Republicans joined Democrats to support Watt. On Millett, three Republicans voted present and two voted with Democrats. Significantly, Arizona Sen. John McCain (R-Ariz.), who was key to the July agreement that ended the Democrats' threat to revise Senate rules, voted with his party to block both choices. McCain urged Reid from the Senate floor to proceed cautiously before considering any radical steps such as changing Senate rules. "Our approval rating with the American people has sunk to all-time lows and [the American people] are going to see another expression of gridlock when we take these votes today," he said. But the cure is going to have repercussions for generations to come. It's unclear when or whether Reid might attempt to change the filibuster rules. Any changes would also apply to Democrats when they are the minority party in the Senate, and they have relied on the filibuster tool in the past. But Reid's Democratic members - many of whom have only served in the majority - are keen to pursue the rule change. Sen. Jeff Merkley, a first-term Democrat from Oregon and one of the leading advocates of changing filibuster rules, said Republicans' back-to-back votes Thursday amounted to a "war on the other two branches of government and their ability to do the jobs the American people need them to do." The longest-serving Democrat, Judiciary Committee Chairman Patrick J. Leahy of Vermont, said that by blocking Millett, "Republicans have injected politics into the one branch that should remain free of politics." He urged the Republican senators who helped broker the deal to end the government shutdown to support her nomination. A senior leadership aide emphasized that there would be no immediate attempt to change Senate rules, and that conversations with Republicans continued that could pave the way for the nominations of Watt and Millett to advance. But the aide, granted anonymity in order to candidly discuss the strategy, said that circumstances could change based on how Republicans responded to further nominations. Reid is likely to bring to the floor a second of three nominees Obama made this summer to the D.C. Circuit, Nina Pillard. Also Thursday, the Senate Judiciary Committee approved, along strict party lines, the third nominee for the 11-member panel, Robert Wilkins.