The selection of Kerry sets a pragmatic tone as Obama begins reshaping his national security team, which will include a new CIA director.

Kerry will be the leading Cabinet member charged with tackling a range of thorny global challenges, including Middle East upheaval, Iran’s nuclear standoff with the West and winding down the war in Afghanistan - all at a time of fiscal austerity at home.

CLOSE TIES TO OBAMA

Kerry has forged close ties with Obama, and gave him the keynote speech assignment at the 2004 Democratic convention that boosted him to the national stage and opened the way for his meteoric rise.

After losing narrowly to Republican George W. Bush in the 2004 presidential election, Kerry forged a new identity as a congressional leader on foreign policy. He often served as a low-profile emissary and diplomatic troubleshooter for the Obama White House in places like Afghanistan, Pakistan and Syria.

But White House aides acknowledge that Kerry could be handicapped somewhat for lacking the close personal bond that Rice has with Obama.

On top of that, Kerry’s departure from the Senate forces Democrats to defend his seat. Just-defeated but still-popular Massachusetts Republican Senator Scott Brown, who took office in early 2010 after winning the last special election for a Massachusetts seat, is widely expected to run.

Obama had originally weighed rolling out his top national security appointments in a single package this week. But the controversy over Hagel apparently led the White House to take a more piecemeal approach.

The administration on Thursday joined allies rallying to support Hagel against an onslaught over his record on Israel and Iran led by some pro-Israel groups and neo-conservatives, but also including some former colleagues on Capitol Hill.