If any group appears to have suffered from the fatigue brought on by the all-day political coverage, it is the cadre of Democrats running for president. A prime-time debate in Atlanta on Wednesday, the fifth of the year, drew the smallest live viewership of the Democratic primary campaign so far, with 6.6 million tuning in to MSNBC .

That debate followed roughly 11 hours of live testimony, a test for even the most dedicated TV political junkie. And it featured 10 candidates who have grown familiar to viewers, whereas the impeachment hearings, like the Watergate sessions of the 1970s, are minting a fresh group of small-screen stars.

Previously obscure civil servants, like Fiona Hill, a former White House Russia expert, and Gordon D. Sondland, the American ambassador to the European Union, are suddenly household names. On his CBS late-night show on Tuesday, Stephen Colbert delivered a riff on the decorated résumé of Lt. Col. Alexander S. Vindman, joking, “The only way Vindman could be more all-American is if he appeared in a Ken Burns documentary about the Statue of Liberty — which he did as a child.”

Seizing the moment, late-night comedy shows are scrambling to book political figures and pundits. In the last couple of weeks, Mr. Colbert welcomed the MSNBC host Nicolle Wallace and Senator Kamala Harris of California. On NBC’s “The Tonight Show Starring Jimmy Fallon,” the host, who rarely wades into politics, made an exception last week when he chatted about impeachment with Ms. Maddow .

The impeachment-focused fare seems to be working: Mr. Colbert is soundly beating his rivals Mr. Fallon and Jimmy Kimmel of ABC in the ratings.

Not to be outshone on his favorite medium, President Trump took to the airwaves himself on Friday morning, calling into “Fox & Friends” for a 53-minute-long defense of his actions, in which he asserted a number of falsehoods about Ukraine.

Over all, Fox News is the most popular venue for daytime viewers to watch the congressional hearings. The network averaged about 2.5 million people over five days of coverage, according to Nielsen.