Monday's U.S. Supreme Court case on the president's power to temporarily fill high-level posts will bring a ruling that could echo for centuries, a lawyer said. "Rulings like this have implications that last for centuries," Michael Lotito, an employment and labor attorney with law firm Littler Mendelson P.C.'s Workplace Policy Institute, told the Hill newspaper. Presidents since George Washington have made recess appointments of judges and senior federal officials who would normally require Senate confirmation, relying on Article II, Section 2 of the Constitution, which lets presidents temporarily fill vacancies while the Senate is in recess. Recess appointments must be approved by the Senate by the end of the next congressional session, or the position becomes vacant again. But during the partisan struggle between the Obama administration and the Senate over presidential nominations, Obama became the first president to appoint nominees when the Senate was in a "pro forma" session -- a brief call to order and adjournment held every few days at which no formal business was expected to be conducted. The sessions, when only a handful of senators are usually present, have been used to prevent recess appointments. But the Obama administration claimed the Senate was not really available during those sessions to live up to its constitutional responsibility to provide "advice and consent" for presidential appointments, so the administration said Obama's recess appointment power was in effect. "The sham pro forma sessions are nothing more than that," Catholic University law Professor Victor Williams, who filed a brief backing the government's position, told the Hill. Obama temporarily appointed three people to the National Labor Relations Board, which lacked a quorum to conduct business, Jan. 4, 2012. The Senate held a pro forma session the day before, with one senator presiding. A soft drink bottler in Yakima, Wash., later argued the NLRB appointments were unconstitutional after the labor relations board ruled against the bottler in a dispute with the Teamsters union. The NLRB panel that made the ruling included two board members assigned by Obama as recess appointments. The U.S. Court of Appeals for the District of Columbia Circuit agreed with Noel Canning, ruling a president could make recess appointments only during the period between the official end of one congressional session and the start of another. It also ruled a president could use his recess appointment authority only to fill vacancies that arose during the formal recess, not beforehand. The NLRB vacancies arose before the December 2011 end of the 111th Congress and the January 2012 start of the 112th. A Congressional Research Service report found 329 recess appointments since President Ronald Reagan in 1981 would not meet the appeals court's criteria and could therefore be ruled void if the appeals court's ruling is upheld. Upholding the appeals court's decision "would repudiate the constitutional legitimacy of thousands of appointments made by at least 14 presidents since the 1860s," Solicitor General Donald Verrilli wrote in a brief. Verrilli argued the Senate was not permitted to use pro forma sessions to unilaterally hamstring or manipulate the president's recess appointments authority. "Whatever leeway the Senate may enjoy when governing its own affairs, it cannot exploit that leeway to limit the president's constitutional authority," he wrote. But Noel Francisco, a Washington appellate lawyer challenging the recess appointments, argued it was up to the Senate, not the president, to decide when the Senate is in session. "Presidents have discretion to decide whether to make recess appointments, and to select whom they appoint. But they may not also determine when that power is available," Francisco said. "That decision is for the Senate alone."