By Maria Caspani NEW YORK (Reuters) -The holiday weekend brought dangerous freezing temperatures across much of the United States, snarling everything from political campaigning to football games and travel, and knocking power out to about 350,000 customers in the Northeast and Pacific Northwest. An Arctic blast from Canada caused temperatures to plummet across a vast swath of the country, from the Northwest into the Rust Belt, the U.S. National Weather Service (NWS) said in a Sunday bulletin. “To highlight just how intense this outbreak of Arctic air is, over 95 million citizens fall within a…