Mr. Kerry’s remarks drew applause from the crowd, but they also pointed to a dilemma for Mrs. Clinton in the effort to define her tenure as secretary of state. She did devote much of her time at the State Department to advancing women’s and girls’ issues and believes those efforts have deeper implications in democratization and diplomacy.

But some people close to Mrs. Clinton worry that, because of the high profile given to her work for women’s rights, and the headlines now being generated by the hyperkinetic Mr. Kerry, her efforts on trickier diplomatic situations have been eclipsed.

What about her 13 trips to Libya in 2011 to build the coalition that led to the ouster of Col. Muammar el-Qaddafi, they ask. Why is no one talking about how she brokered a cease-fire in Gaza? Anyone remember that she furthered economic sanctions on North Korea?

The struggle to define Mrs. Clinton’s accomplishments at the State Department has intensified in recent days as Mr. Kerry and his latest assertive diplomatic effort — a successful push for an agreement with Iran that would temporarily curb the country’s nuclear program — have drawn tough comparisons with Mrs. Clinton.