The Democratic primary race, with more than half the delegates still in play, is now between Bernie Sanders and Joe Biden. They have radically different policy platforms and political strategies, but for many voters, the most pressing concern is which of these two men has the best shot of beating Donald Trump in November.

Fundamentally, we worry that Biden is not running an inspiring campaign that can win. His message to struggling young people is “give me a break” — things aren’t so bad. His message to climate activists and immigration activists who challenge his positions is “go vote for someone else.” And his message to Wall Street is “nothing will fundamentally change.”

The only Democrat to win the presidency since Bill Clinton was Barack Obama. Obama ran significantly to Hillary Clinton’s left in the primary, inspiring a generation with his vague but uplifting message of “hope and change.” Moderate Democrats who didn’t run inspiring campaigns, such as Al Gore, John Kerry, and Hillary Clinton, didn’t fare well.