The GOP convention may have been delayed, but Fox News wasted no time in crushing TV rivals with Tuesday coverage of the gathering's first full day.

During the 10 p.m. Eastern hour, when the broadcast networks were airing live coverage of the Republican National Convention in Tampa, cable's Fox News was No. 1 among all outlets, averaging 6.9 million total viewers, according to early data from Nielsen.

That was well ahead of runner-up NBC, which averaged 5.4 million, not to mention CBS (3.3 million) and ABC (2.3 million). CNN and MSNBC tied with 1.5 million apiece.

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The night was dominated by coverage of a speech by Ann Romney, the wife of GOP presidential contender Mitt Romney. (Not everyone was seduced by the prospect of long political speeches: The night's most-watched program was NBC's "America's Got Talent," with more than 10 million tuning in, partly explaining NBC's victory over CBS and ABC at 10 p.m.)

The results add grist to the notion that Fox News' core viewership is more engaged with Republican than with Democratic politics. Fox News' numbers were slightly higher than for the 10 p.m. hour of the Tuesday of the GOP convention in 2008 (6.2 million). That same year, Fox's numbers were much lower for the Democratic confab, with the first night averaging around 3 million in prime time. That pattern will likely be repeated next week when the Democrats meet in Charlotte, N.C.

For the night overall, Fox averaged 5.2 million viewers, more than three times the totals for MSNBC and CNN. The cable networks were forced to intersperse heavy convention coverage with reports of Hurricane Isaac's landfall in Louisiana. Monday's scheduled Day 1 of the convention was delayed due to the storm's brush past the Florida coast.

Especially noteworthy is CNN's ongoing decline. In 2008, CNN drew 3.2 million during the 10 p.m. hour of its GOP Tuesday coverage, meaning it has lost more than half its audience since then.

The broadcasters, as they did in 2008, trimmed their convention coverage to the 10 p.m. hour, airing regular programming earlier in the evening.