By JIM KUHNHENNWASHINGTON (AP) â¿¿ President Barack Obama nominated White House chief of staff Jack Lew to be treasury secretary Thursday, declaring his complete trust in an aide with three decades of Washington experience in economic policy and a penchant for shunning the limelight. "He is a low-key guy who prefers to surround himself with policy experts rather than television cameras," Obama said. Obama announced his nomination in the ornate White House East Room, flanked by Lew and outgoing Treasury Secretary Timothy Geithner. The two men and their backgrounds illustrate the nation's changing economic landscape. Geithner is a longtime banking specialist with the Treasury and the Federal Reserve who took office in 2009 at the height of the nation's financial crisis. Lew has been a budget expert as the government struggled with its debt and deficit challenges. Obama heaped praise on Geithner for addressing the Wall Street meltdown and shepherding an overhaul of financial regulations through Congress. "When the history books are written, Tim Geithner is going to go down as one of our finest secretaries of the treasury." Obama highlighted Lew's past work on economic policy, from his days in the 1980s as an aide to then-House Speaker Tip O'Neill to his work on the budget with President Bill Clinton. Obama delighted in singling out Lew's loopy signature, a distended Slinky-like scrawl that captured media attention Wednesday, joking that when he became aware of it he considered "rescinding my offer to appoint him." If confirmed as treasury secretary, Lew's signature will appear on U.S. currency. A year ago, almost to the day, Obama selected Lew as his chief of staff, taking him from his job as director of the Office of Management and Budget into the White House's tight inner circle. In selecting Lew to replace Geithner, Obama not only picks an insider steeped in budget matters but also a tough bargainer. Some Republicans complain that Lew has been unyielding in past fiscal negotiations, particularly the failed talks for a large deficit reduction deal in the summer of 2011. Some have bristled at what they say is a greater desire by Lew to persuade them rather than negotiate.