U.S. Representative Gabrielle Giffords, the lawmaker shot by a gunman in her Arizona district on Saturday, had previously warned that overheated political rhetoric had prompted violent threats against her and vandalism at her office.
"It's important for all leaders ... to say, 'Look, we can't stand for this," Giffords told MSNBC last March, when a window in her Tucson office was smashed after Congress passed President Barack Obama's landmark healthcare overhaul.
Giffords said she faced a deluge of threats for her support of the healthcare bill.
"We've had hundreds and hundreds of protesters over the course of the last couple of months," Giffords told MSNBC. "Our office corner has really become an area where the Tea Party movement congregates and the rhetoric is really heated. Not just the calls but the e-mails, the slurs."
A Democrat with a centrist voting record who had just begun her third term, Giffords fended off a tough challenge last year from Republicans who hoped to win control of the politically competitive district.
Her opponent in the November election urged followers to "Get on target for victory" and help "remove" Giffords from office at a June event in which participants could shoot an automatic rifle.
Former Alaska governor Sarah Palin, a prominent conservative, for months used a graphic of a gun cross-hairs to urge followers to "reload" and "aim" for Giffords and other Democrats.
"When people do that, they've got to realize that there's consequences to that action," Giffords told MSNBC.
On Saturday, Palin had removed the graphic from her website and offered her condolences on a posting on Facebook.
"We all pray for the victims and their families, and for peace and justice," Palin said, speaking of Saturday's shooting when at least five were killed and 18 in all shot.
Aside from healthcare, Arizona is the focal point of a rancorous debate about illegal immigration. Giffords, whose district borders Mexico, backs a comprehensive reform that would combine tough border security with a long-term path to citizenship for illegal immigrants.
Giffords' shooting drew condemnation from across the political spectrum, including from leaders of the grass-roots Tea Party conservative movement, which has opposed healthcare reform and Giffords' approach to immigration in often heated terms.
House Republican leader Eric Cantor said he would postpone a vote scheduled for next week to repeal the healthcare law in light of the shooting. Repealing healthcare reform is a priority of Republicans who won control of the chamber in the November elections.
"It is horrifying that she was exposed to such violence at an event designed to reach the people she represents," Cantor said in a statement.
U.S. lawmakers receive a steady stream of harassing phone calls, e-mails and letters, according to the U.S. Capitol Police. At least two men are currently serving prison sentences for threats they made to backers of the healthcare reform legislation.
Capitol Police warned lawmakers to take "reasonable and prudent precautions" after the shooting.
A Democratic congressman from Arizona complained about blogs and television shows that spew hate against politicians.
"People think now if they want to make a statement, they can do that by bringing bodily harm to someone who doesn't agree with them," Representative Ed Pastor said on CNN.
Republican Representative Trent Franks, also from Arizona, said it was premature to ascribe political motives to the shooting.
"I'm afraid that really what has happened here is you've got a lunatic that just unhinged, that's an evil degenerate," Franks said in an interview with CNN.