PHOENIX -- Presidentelect Barack Obama formally named Gov. Janet Napolitano Monday as his choice for Secretary of Homeland Security, saying she has "the experience and executive skills we need.''

"She has spent her career protecting people,'' the presidentelect said, citing her experience as the U.S. Attorney for Arizona, the state attorney general and as governor.

"She understands the needs for a Department of Homeland Security that has the capacity to help prevent terrorist attacks and respond to catastrophes, be it manmade or natural,'' he continued. Obama said Napolitano has "learned the lessons, some of them painful, of the last several years,'' specifically mentioning the Sept. 2001 terrorist attacks and Hurricane Katrina.

Napolitano, for her part, said she and the rest of Obama's "national security team'' announced Monday will "plan carefully and thoroughly so that our domestic response to all hazard is fast, sound, levelheaded and effective.''

"Americans deserve no less,'' she said.

Napolitano acknowledged she is quitting as governor only halfway through her second fouryear term.

"It is difficult to leave one job for another,'' she said. "But one must go where one can best serve.''

The governor also said she was not breaking any promises by quitting to become part of Barack Obama's administration.

Nor does she believe she misled anyone when saying, in response to questions about staying through 2010, that she likes her job and is not looking for another.

Napolitano said all that was true -- to a point.

"So, while I did not campaign for the job, when he called and tendered it to me it was certainly something that I had to take seriously,'' she said. "And obviously I did.''

The governor admitted, though, she has been talking with Obama about a Cabinet post "for several weeks.''

"I think people will understand the difficulty of the choice but the reason behind the choice that I made,'' she said.

Despite Monday's nomination, Napolitano is not giving up the reins of state government just yet.

The governor said she intends to prepare a budget for the coming fiscal year even though she is unlikely to be around to try to shepherd it through the Legislature. And Napolitano said she will deliver a State of the State speech in January laying out her priorities for the upcoming legislative session. (See related story)

But Napolitano said she does intend to quit the moment she is confirmed by the U.S. Senate, something that could occur within days of Obama being sworn in on Jan. 20.

In none of her comments in Chicago or Phoenix did Napolitano make mention of leaving the state with a $1.2 billion deficit for the current year and an even larger gap between anticipated revenues and expenses in the fiscal year to come. Instead, she said that Secretary of State Jan Brewer, who will become governor the moment that Napolitano resigns, will inherit the job "during this difficult time, without having sought this office.

In Monday's announcement in Chicago, the presidentelect said Napolitano brings some special qualifications.

"She understands as well as anyone the dangers of an unsecure border,'' he said. And Obama said he expects Napolitano to be "a leader in reforming a sprawling department while safeguarding our homeland.''

Napolitano, however, refused to say what changes she intends to bring to the agency with its 218,000 employees.

"I don't think it's appropriate for me to answer those questions right now,'' she said. "There'll be plenty of time to talk about that.''

The governor said she wants to meet first with federal lawmakers who sit on committees that have oversight of her new agency.

The appointment drew praise from current Homeland Security Secretary Michael Chertoff, who has met repeatedly with Napolitano on border issues.

"She has a tremendous intellect and possess the leadership and sound judgment needed to make the difficult decisions that this job presents,'' he said. Chertoff made no mention of the times that Napolitano has criticized him -- and his agency -- over issues ranging from the adequacy of a "virtual fence'' being erected in southern Arizona to the decision to end a program which had put National Guard troops along the border.

U.S. Sen. Susan Collins, R-Me., the ranking Republican on the Senate Homeland Security and Governmental Affairs Committee, said she will work with the majority Democrats "to consider this nomination carefully and expeditiously. Collins, in a prepared statement, said Napolitano, as governor of a border state, "understands the importance of developing policies that will not impede legitimate travel and trade but will keep our enemies out.''

Both Obama and Napolitano promised better relations with the states.

The president-elect said the governor "knows firsthand the need to have a partner in Washington that works well with state and local governments.'' And the governor said the agency she has been named to head will "work handinhand with state and local governments to share information, secure our borders and keep our country safe.''