Senate Majority Leader Harry Reid, D-Nev., likened them to "anarchists" and "fanatics."
When a gunman in Tucson, Ariz., went on a shooting spree in 2011, killing six and critically wounding then-Rep. Gabrielle Giffords, lawmakers from both parties called for a reset in confrontational politics.
Easier said than done.
"What we're not for is negotiating with people with a bomb strapped to their chest," Obama's senior adviser, Dan Pfeiffer, told CNN this past week.
Jon Favreau, who was Obama's chief speechwriter the last time the U.S. faced such brinksmanship over the debt ceiling, in 2011, said he remembers hearing then-Treasury Secretary Tim Geithner explain to White House aides just what would happen if the U.S. defaulted.
"On most issues, I'm not a fan of really cranking up the rhetoric," Favreau said. "But on the debt ceiling, because so few people know what the consequences of default really are, sometimes you really need to draw some analogies and really spell it out for people."
Republicans see another cause for alarm as they eye their last-best chance to undo the health law before people start buying insurance through new exchanges that open next week.
But is the law, which also provides protections for Americans with pre-existing conditions and expands coverage options for young adults, really that bad?
"Obamacare is the most dangerous piece of legislation ever passed in Congress," Rep. John Fleming, R-La., has said, calling it the biggest existential threat to the economy since the Great Depression.
New Hampshire state Rep. Bill O'Brien has called it as destructive to personal liberty as the Fugitive Slave Act of 1850, which forced runaway slaves to be returned to their masters.
A conservative group is airing television ads insinuating that women who purchase insurance through the exchanges will be violated by a creepy Uncle Sam using metal gynecological instruments.