Newscaster Tim Russert has died of a heart attack at 58, according to wire services. According to TVNewser:

Around 1pmET this afternoon, Russert was conducting a political Q&A on MSNBC.com. We’re told Russert collapsed while in the tracking booth at the Washington bureau.

Unbelievably shocking, with no sarcasm intended. Thoughts and prayers are with his family.

Update: Responses on the passing from all corners. Sen. McCain, National Review, President of the United States, and NewsBusters Publisher Brent Bozell.