Craig Crawford's Trail Mix

Tonight’s Democratic presidential debate on CNN could and should test the glow of inevitability that Hillary Rodham Clinton’s campaign has meticulously managed to create. But it is up to her rivals to make that happen.

In the debates so far, the rest of the major Democratic contenders have treated the New York senator and former first lady like the boss, taking care not to take her on directly. They save their subtle jabs for the campaign trail, apparently fearing to risk attacks that might backfire in front of nationally televised audiences.

Still, tonight’s format — video questions submitted by the public via You Tube — traditionally does not invite the infighting that journalists often try to provoke when they quiz the candidates.

If Clinton’s nomination is inevitable, Democrats ought to want to see her challenged in ways that Republicans will surely do in a general election. She probably could use the practice, and primary voters need to see how she handles direct attacks.