The Democratic debate Wednesday night was mostly devoid of sharp exchanges between candidates, with the partial exception of a few moments involving also-ran Tulsi Gabbard. To some observers, it was a pleasant and substantive affair; to others—especially reporters searching for a headline—it was a boring anticlimax to a long day dominated by the impeachment hearings in Washington.
The amicable climate was partially due to the MSNBC moderators, who mostly declined to ask questions intended to provoke conflict between specific candidates. Some corners of lefty Twitter credited this dynamic to the fact that all four moderators were women. But female moderators in previous debates have not been reluctant to set candidates against each other; a more likely explanation lies in MSNBC's own house style (personified by Rachel Maddow, the network's biggest star), which sells itself as floating cerebrally above anything that smacks of a mere made-for-TV stunt. Most candidates may also see attacks in a large field as strategically risky unless they can be directed at an easy target like Gabbard.
Biden, Warren, Sanders, and Buttigieg are all doing well enough in the polls—whether in Iowa, nationally, or both—that debate performances aren't critical for their candidacies at this stage in the race (pundits never seem to think Biden does well in these events, but it doesn't seem to be hurting him with voters), and Gabbard, Yang, and Steyer aren't serious contenders for the nomination. That leaves Harris, Booker, and Klobuchar in the position of needing some kind of breakthrough as the days tick down, and all three seemed to have prepared for Wednesday's debate with an eye toward making a memorable impression with viewers. Notably, each of them made an explicit strategic case for themselves as nominees.
The problem is that they are all, to an extent, in competition with each other to attract media and activist attention during a crucial pre-Iowa stretch in which impeachment, not the Democratic primary race, will be the chief national political story. Journalists will probably agree that they all performed well, but none of them is likely to gain the kind of post-debate bounce that Harris got over the summer but couldn't sustain thereafter. For all three, their best path to the nomination remains a better-than-expected showing in Iowa that carries into the succeeding states. But while it's still early, it's not as early as it used to be, and their hopes increasingly depend on a major stumble by one or more of the front-runners.