Hillary Clinton plans to accept the job of secretary of state offered by Barack Obama, who is reaching out to former rivals to build a broad coalition administration, the Guardian has learned.

Obama's advisers have begun looking into Bill Clinton's foundation, which distributes millions of dollars to Africa to help with development, to ensure there is no conflict of interest. But Democrats believe the vetting will be straightforward.

Clinton would be well placed to become the country's dominant voice in foreign affairs, replacing Condoleezza Rice. Since being elected senator for New York, she has specialised in foreign affairs and defence. Although she supported the war in Iraq, she and Obama basically agree on a withdrawal of American troops.

Clinton, who still harbours hopes of a future presidential run, had to weigh up whether she would be better placed by staying in the Senate, which offers a platform for life, or making the more uncertain career move to the state department.

As part of the coalition-building, Obama yesterday also reached out to his defeated Republican rival, John McCain, to discuss how they could work together to roll back some of the most controversial policies of the Bush years. Putting aside the bitter words thrown about with abandon by both sides during the election campaign, McCain flew to meet Obama at his headquarters in the Kluczynski Federal Building, in downtown Chicago.

Obama, speaking before the meeting, said: "We're going to have a good conversation about how we can work together to fix up the country." Asked by a reporter whether he would work with Obama, McCain, who favours a bipartisan approach to politics, replied: "Obviously".

Sources on both sides said Obama did not offer McCain a cabinet job, but focused on how the senator for Arizona could help to guide legislation that they both strongly favour through Congress.

Given Obama's status as president-in-waiting, the two met in a formal setting, a room decked out with a US flag, and were accompanied by senior advisers. Although the two clashed during the election campaign over tax policy and withdrawal from Iraq, they have more in common than they have differences. They both favour the closure of the Guantánamo Bay detention centre, an increase in US troops to Afghanistan, immigration reform, stem cell research and measures to tackle climate change, and oppose torture and the widespread use of wire-tapping.

After the meeting, they issued a joint statement saying: "At this defining moment in history, we believe that Americans of all parties want and need their leaders to come together and change the bad habits of Washington so that we can solve the common and urgent challenges of our time. We hope to work together in the days and months ahead on critical challenges like solving our financial crisis, creating a new energy economy and protecting our nation's security."

Although Democrats made gains in the Senate in the November 4 elections, they fell short of the 60 seats that would have allowed them to override Republican blocking tactics and will need Republican allies to get Obama's plans through. This was highlighted yesterday when the Democratic leadership in Congress announced that a broad economic stimulus package Obama sought was not likely to be passed because of Republican opposition.

Obama confirmed at the weekend that he would offer jobs to some Republicans. One of the names that crops up most often is Chuck Hagel, the former Republican senator who is a specialist in foreign affairs and a critic of the Iraq war.