Washington (CNN) -- It will take an act of Congress to keep Robert Mueller at the helm of the FBI, and all signs indicate that's precisely what lawmakers will do.
No sooner had President Barack Obama announced plans to extend Mueller's statutorily limited 10-year term to 12 years than Democrats and Republicans alike began to smartly salute the decorated Marine and declare the move a grand idea.
"Director Mueller is a true patriot." gushed Senate Intelligence Chairwoman Dianne Feinstein of California, who said the extension will "provide important stability in President Obama's national security team."
The more moderate and independent Senate Homeland Security Chairman Joe Lieberman of Connecticut praised Mueller for exhibiting "vision and leadership during an extremely difficult period".
And, on the conservative flank, House Judiciary Committee Chairman Rep. Lamar Smith of Texas gave full-throated backing to the president's decision, saying, "It is important to maintain continuity for our intelligence community."
Even Capitol Hill's longtime leading critic of the FBI and its culture, Sen. Charles Grassley, R-Iowa, said he is "open to the idea" of the extension, although he cautioned against a possibly "risky precedent."
It was no different in 2001, when then-President George W. Bush appointed Mueller FBI director. The Senate voted for Mueller's confirmation 98-0. White House aides later acknowledged that Mueller had been the only candidate seriously considered.
Observers in the FBI and in Congress privately admit to astonishment that Mueller managed to maintain such strong bipartisan support during a long decade of bitter political polarization. Mueller has been able to deftly fight countless battles -- and win most of them -- during a tumultuous decade dominated by fallout from the 9/11 terrorist attacks and the monumental task of trying to remake the FBI.
Justice and FBI officials attribute Mueller's staying power in large measure to a combination of qualities rare in Washington. He studiously avoids the spotlight and when he's thrust into it he displays a modest, no-nonsense demeanor. Under questioning from lawmakers Mueller exercises great restraint and unyielding discipline.
Despite wide personal support, Mueller's tenure has hardly been a cakewalk. Because a post-9/11 FBI director must wrestle with a host of controversial national security issues, he cannot avoid collecting bureaucratic bumps and bruises and sometimes deep scars.
Mueller had been on the job only a week when terrorists crashed airliners into the World Trade Center and Pentagon and passengers overpowered the hijackers of another over Pennsylvania and crashed it. Mueller and his immediate boss, Attorney General John Ashcroft, had to react to intense pressures from inside and outside of the government. Who was responsible for this?
As evidence rapidly mounted that the FBI had missed important clues that may have prevented the terrorist attack, Mueller publicly vowed the FBI would be transformed to fix the gaping communication and investigative gaps.
It also meant Mueller would have to fend off calls for a new intelligence agency not tied to law enforcement. Advocates of a British-style MI-5 agency locked horns with Mueller who fervently believed the FBI was capable of serving as both an intelligence agency and a law enforcement agency.
Slowly, but surely, Mueller prevailed, and that crucial victory allowed him to doggedly rebuild the FBI into a modern intelligence-driven agency.
Mueller's FBI has as its overriding mission the prevention of terrorist attacks on U.S. soil, not traditional crimefighting and mob-busting. Those missions exist but have necessarily taken a back seat to counter-terrorism.
The FBI record on the new playing field is getting better, but is not perfect. Early on, the FBI's investigation into deadly anthrax-laced envelopes mailed to lawmakers and journalists lasted for several years -- and focused on the wrong suspect -- before it was finally solved.
Mueller's FBI failed to detect potential warning signs which may have prevented the deadly shooting at Fort Hood, Texas. Thirteen people died in the rampage allegedly by Maj. Nidal Hasan, an Army psychologist.
In the case of would-be underwear bomber Umar Abdulmutallab, the FBI and others were on the defensive. After the Christmas Day, 2009, in-air attempt by Abdulmulllab to detonate explosives sewn into his underwear, agents took custody of the suspect, but it was unclear who was in charge and when his Miranda rights should have been given to him. Mueller was called before the Senate in January, 2010 to try to explain.
Some of Mueller's most bruising battles dealt not with terror plots, but with terrorism policy.
Mueller's greatest challenge came in March, 2004 when the director penned a resignation letter to Bush. Mueller agreed with acting Attorney General James Comey that a secret National Security Agency domestic surveillance program was illegal.
After Comey and Mueller rebuffed attempts by White House emissaries Andy Card and Alberto Gonzales to have Ashcroft reauthorize the program from his hospital bed, Comey and Mueller were called to see the president.
Mueller said he would resign. Bush backed down and Mueller stayed on. The story remained secret until 2007, when it exploded and led to a dramatic hearing.
Comey forthrightly testified, but Mueller in keeping with his nature, tried to avoid confrontation. Mueller acknowledged that he agreed with Comey's version of events, and when asked point blank if he thought the warrantless wiretapping program was illegal he said "yes."
Mueller survived one other confrontation with Bush. When FBI agents raided Rep. William Jefferson's office seeking evidence of corruption, lawmakers exploded with fury. They claimed the Bush Justice Department had violated the established separation of powers. When Bush in negotiations said the FBI should return the documents to Jefferson, Mueller said no. Bush then agreed to let Mueller keep the documents, but sealed until a legal challenge was settled. When the courts ruled in favor of the FBI raid, the documents were available to help convict Jefferson.
Mueller's standing up to Bush won him great praise from Democrats, while Republicans took comfort in the growing stature of a key figure in the Bush administration and Justice Department.
Mueller's knack for making good decisions is not a new-found skill. His decision to return to the Justice Department at a working level in 1995 raised a few eyebrows but was embraced by his old colleagues.
Indeed, nothing endeared Robert Mueller to federal prosecutors and field agents so much as his decision to turn his back on the fat paychecks and fancy digs of an elite Boston law firm to become -- again -- a federal homicide prosecutor.
Agents and attorneys who know him best say he made the move to the U.S. Attorney's office in Washington for one reason alone: He is a prosecutor at heart and he believed he belonged at the Justice Department.
Robert S. Mueller III was born into an affluent family and attended prep schools before enrolling at Princeton. With his Ivy League degree, he collected a master's degree in International Relations at New York University and a law degree from the University of Virginia.
When he received a fistful of medals for combat in Vietnam, all of the boxes were checked in a career destined for success. But aides and friends say Mueller's two stints in private law didn't satisfy him, so he came back to public service. In 1998 he was named U.S. attorney in San Francisco, and three years later was named FBI director.
Now, 10 years later, he's on the cusp of being officially irreplaceable.