A shaky debate performance last week caused members of the Democratic party to question if the 81-year-old incumbent is the right choice as their candidate.

A New York Times/Siena College poll showed that 69 percent of voters, including 55 percent of Biden voters, said Biden is too old to be an effective president.

Could Democrats change their plans as the party gears up for their national convention in late August?

Elaine Kamarck of the Brookings Institution studies the presidential nomination system. She joins Midday to discuss what could happen in the coming weeks.