ANALYSIS: On Attack, Hillary Clinton Regains Control of Democratic Race

Las Vegas, Nevada -- The Democratic race for president was Hillary Clinton’s at the start. She owned it when the candidates finally met on stage.

Clinton used the first debate of the campaign to reaffirm control against four challengers who struggled to and sometimes outright refused to bring the fight to her. She delivered a feisty, aggressive performance that flipped the expected script: Rather than take the barbs, she dished them out.

Bernie Sanders took the brunt of Clinton’s attacks. She countered Sanders’ passion with a message about something that also matters to primary voters –- getting things done.

But more significant was what happened in the other direction.

Confronted with Clinton’s vulnerabilities, Sanders –- as he has on the trail -– declined to engage. His response may have the impact of neutering the much-discussed stories about her emails for a good stretch of the Democratic primary race.

“The American people are sick and tired of hearing about your damn emails,” Sanders yelled. He earned a broad smile and a handshake of thanks from Clinton, in addition to a standing ovation from the audience.

Lincoln Chafee protested that it does matter. Asked whether she wanted to respond, Clinton essentially dropped the mic: “No.”

She didn’t have to respond Tuesday night, as she dominated the four men who flanked her on stage.

That isn’t the same as saying she has mollified concerns about her candidacy. Democrats know the email story is one of her real vulnerabilities in a general election; one can only wonder if Joe Biden, watching from the vice president’s residence back in Washington, agrees.

Clinton’s performance underscored her strengths, in particular her campaign-tested toughness. For the night –- and it might not last longer than that, to the chagrin of Democrats -– it also obscured her still-considerable weaknesses.

A non-answer on legalized marijuana and a parody-worthy response on the Keystone pipeline –- “I never took a position on Keystone until I took a position on Keystone” -– were reminders of the kinds of things that give Democrats pause about her candidacy. Republicans, of course, won’t agree that Americans have heard too much about Clinton’s emails.

To some extent, Clinton has always been running against herself –- her own backstory, contradictions, and shortcomings. The first debate was a big step toward Clinton reclaiming that history for this race.

Sanders -– who has drawn huge crowds and big dollars to his progressive cause –- helped Clinton find a groove, in both his refusal to outright attack, and his role as a foil.

"I'm a progressive. But I'm a progressive who likes to get things done,” Clinton said, in an unmistakable reference to the self-described “independent socialist” senator from Vermont.

The debate was substantive and engaging, if Clinton’s rivals didn’t all seem to belong on the stage with her. It revealed a Democratic party with disagreements, though not in disarray.

Sanders was Sanders, barely deviating from a script that’s gotten him farther than almost anyone expected he could get. He may not have intended to do Clinton a favor on her emails, though it might have had that effect.