While Flournoy is still a strong contender, six people close to the transition say Biden is not entirely sold on the woman who was widely seen as Hillary Clinton’s pick for Defense secretary if she had won the presidency in 2016.

Two former Obama White House officials who remain close to Biden said he never developed the kind of strong personal relationship with Flournoy that he has sought in his Cabinet picks, and once the dust settled after the election, Biden began leaning toward exploring other options.

Another top contender is Jeh Johnson, Obama’s second secretary of Homeland Security, the people said. He would be the first Black Defense secretary in an administration that has promised a diverse Cabinet.

“Michèle is still at the top of the list but they still want to keep looking — and that’s a change,” said a former senior national security official tracking the transition closely. The sense is: “Let’s not be rushed here.”