I read the article and what Barr said is they have legal power to send agents and the agents are available if needed. Though there seems to be the cavate of: if the states ask for help. If they don't ask, they don't send? Who can "officially ask" is what I wonder? Can Trump send them?

Particularly in certain big cities, I don't think they'll be able to watch the counting without force. They aren't letting people in and the local authorities are siding with their corrupt bosses. (Well, when your mayor is corrupt, naturally most of your cops will be too. That's how it was in the mafia era.)