Ridge steps down as Homeland Security chief
Former Pennsylvania governor was first to oversee department
(CNN) -- Homeland Security Secretary Tom Ridge resigned Tuesday, but he will remain in the post until February 1 unless a successor is confirmed sooner.
"There will always be more to do, but today, America is significantly stronger and safer than ever before," he said in his resignation letter. (Ridge's letter)
Ridge later told reporters: "The president has given me an extraordinary opportunity to serve my country in this incredible period since September 11th, 2001."
"I think we've accomplished a great deal in a short period of time," Ridge said. "We have to be right a billion-plus times a year. ... The terrorists only have to be right once."
President Bush hailed Ridge's efforts as the nation's first-ever secretary of the Department of Homeland Security, overseeing its 180,000 personnel.
"His efforts have resulted in safer skies, increased border and port security, and enhanced measures to safeguard our critical infrastructure and the American public," Bush said in a written statement. "In the fight against terrorism, he has played a vital role in protecting the American people from a real and ongoing threat."
Asked during a news conference in Washington what he plans to do next, Ridge said: "I am going to step back a little bit, breathe deeply and then decide."
The former two-term governor of Pennsylvania added that, after 22 years in public service, he plans to get more involved in personal and family matters.
"I am looking forward to going to my son's rugby games," he said.
Ridge, 59, met with Bush on Tuesday morning before the president headed to Canada. According to one official, he then met with his department's senior staff members and told them of his plans to leave.
Ridge accepted the job of homeland security adviser to Bush just days after the September 11 attacks, and stepped into the job of secretary in January 2003 as 22 government agencies were blended into the Department of Homeland Security. The department was charged with developing and coordinating a national strategy to protect against terrorist threats in the United States.
Perhaps his highest-profile move was to oversee the creation of the color-coded threat-warning system. During his time as adviser and secretary, the national threat level was raised from yellow (elevated) to orange (high) and back six times. It is currently at yellow.
Bipartisan praise for Ridge
Ridge has won praise for tackling what was widely regarded as an exceedingly difficult job. But many outside observers say the department is falling short of delivering what it should and could.
Some outside analysts also felt that Ridge lost a number of important battles and said they were hoping his replacement would be able to get more money and therefore more clout for the department.
"Tom Ridge is a decent man and a fine public servant but unfortunately was not given the leeway or resources to tighten up homeland security in the way it should be done," said Sen. Charles Schumer, a New York Democrat. "We hope that whoever the administration chooses to succeed him will be given the tools needed to really do the job."
Sen. John Cornyn -- a member of the immigration, border security and citizenship subcommittee -- praised Ridge's performance.
"Tom Ridge has provided strong and resolute leadership in the fight against terror during his service as America's first secretary of homeland security," the Texas Republican said.
And California Rep. Jane Harman, the ranking Democrat on the House Permanent Select Committee on Intelligence, said Ridge "has made real progress under difficult circumstances."
Ridge served as Pennsylvania governor from 1995 to 2001. He was known for his aggressive technology strategy that helped fuel the state's advances in economic development, education, health and the environment.
Several in running to take over job
It is unclear who will replace Ridge.
If Ridge's successor is a department insider, Asa Hutchinson, the undersecretary for border and transportation security, is a potential candidate. He has maintained a fairly high profile, but has drawn criticism from both parties for comments he has made on immigration.
In September he told The Washington Times that it was "not realistic" to expect authorities to arrest all illegal immigrants. In August, he outlined a number of incentives that could encourage immigrants to apply for Bush's proposed guest worker program.
Hutchinson served as a Republican congressman from Arkansas from 1997 to 2001.
Others who might be considered for the post include Bush homeland security adviser Frances Townsend, whose experience includes stints in the Coast Guard and the White House. She is regarded as someone who has the ear and respect of the president.
Mitt Romney, the governor of Massachusetts, is also among possible contenders. He took over the Salt Lake Organizing Committee for the 2002 Winter Olympic Games and was credited with turning around the scandal-ridden group.
Mike Leavitt, administrator of the Environmental Protection Agency, will also draw consideration. He was governor of Utah during the Olympics and played a hand in security preparations there.
Ridge the latest to leave administration
The administration has been busy in the weeks since the election, which have also seen the resignations of Attorney General John Ashcroft, Secretary of State Colin Powell, Commerce Secretary Don Evans, Education Secretary Rod Paige, Agriculture Secretary Ann Veneman and Energy Secretary Spencer Abraham.
So far, Bush has named four replacements, mostly close associates. He nominated White House counsel Alberto Gonzales to succeed Ashcroft, national security adviser Condoleezza Rice to take over at the State Department and domestic policy adviser Margaret Spellings to replace Paige. On Monday, Bush selected Carlos Gutierrez to be the next commerce secretary.
All of the Cabinet nominees must be confirmed by the Senate.
Ridge, in the past, had declined to be specific when answering questions regarding his future. In July there were reports Ridge told colleagues he was considering stepping down after the election because of job stresses and the need to earn money in the private sector to pay his children's college costs.
CNN's Jeanne Meserve and Mike Ahlers contributed to this report.