Welcome to the Stephen Colbert primary

(CNN)Iowa. New Hampshire. Donor enclaves on the coasts. And… the Ed Sullivan Theater? Colbert’s studio is a logical place for Democrats to tease presidential campaign plans. He has a liberal fan base dating back to his days on Comedy Central, and that audience crystallized after Colbert took aim at then-candidate Donald Trump in 2016. The anti-Trump bent of Colbert’s “Late Show” helped the late-night host win more and more viewers. For the past two years, he has been the highest-rated host in late night. Lately he has also been challenging Jimmy Fallon in the key 18- to 49-year-old demographic, which is especially coveted by advertisers. Colbert’s interviews with politicians have not been a drag on the show’s ratings. If anything, …