Broadcast networks will give wall-to-wall political coverage, only a recent move for a midterm election.

For the second consecutive midterm election cycle, the broadcast networks are preparing to hand over their entire prime-time blocks to election coverage.

This is not how it used to be. In previous cycles, midterm election nights usually garnered an hour of special coverage, in the 10 p.m. hour Eastern time.

But with viewership totals surging during major political events over the past six years, and ratings for sitcoms, reality series and dramas rapidly falling, the networks have been happy to go wall-to-wall with their news divisions for the night.

In 2018, 36.1 million viewers watched prime-time television coverage of the midterms on cable news channels and the broadcast networks, besting viewership totals of previous nonpresidential election cycles going back to 2002, according to Nielsen.

NBC, ABC and CBS captured nearly 15 million viewers on election night in 2018. By comparison, on Monday night, those three networks averaged just over 10 million viewers between 8 and 11 p.m. Eastern time, according to Nielsen.

Before 2018, network and cable news coverage focused on major Senate and governor races. But with most networks now deploying and investing in sophisticated in-studio maps, there is also an emphasis on detailed coverage of House races.

Still, on a night with hundreds of races, it takes patience for a portrait to emerge, and the extra airtime can lead to misleading narratives. In 2018, broadcast and cable networks spent the first 90 minutes of their prime-time coverage emphasizing Florida races, which were going poorly for Democrats. Many anchors and pundits concluded that it was a bad sign for that party. George Stephanopoulos of ABC News declared that the Democrats were “having a disappointing night,” and CNN’s Van Jones said the midterms were “heartbreaking” for liberals.

That would soon change. Fox News was the first network to declare that the Democrats would recapture the House a little after 9:30 p.m. Shortly thereafter, the networks switched gears and laid out how it was actually a successful night for progressives.

This year, all three broadcast networks will also simulcast their coverage online, on CBS News Streaming, NBC News Now and ABC News Live.