President Obama’s State of the Union address drew 37.8 million viewers Tuesday. It was the smallest audience of the four such speeches he has given to joint sessions of Congress.

But, shown on 14 different networks, the address had far more viewers than, say the other dose of political speech that has invaded prime time lately, the Republican Debates, the latest of which drew 7 million Monday on NBC.

Last year’s State of the Union drew 42.8 million, according to Nielsen, with 48 million in the audience in 2010 and a whopping 52.3 million watching in 2009.

Of the networks, NBC had the biggest audience for the speech Tuesday with 8.2 million, CBS followed with 7.3 million and ABC trailed with 6.6 million.

But the biggest network audience Tuesday was for a repeat of Sunday’s late night episode of “American Idol,” which drew 9.6 million.