"This hateful crime is a tragedy beyond words," Sen. Kirsten Gillibrand (D-N.Y.) said in a statement. Gillibrand has held constituent meet-and-greets at supermarkets and shopping centers similar to the one where Giffords was shot.
"I think it is deeply regrettable," he said. "It moves us further away from where we need to be as a country."
Sen. Charles Schumer (D-N.Y.) called the attack "senseless and savage" and said, "The individual who perpetrated these attacks must face swift and certain justice." He called Giffords a trailblazer and said she was the youngest woman from Arizona ever elected to Congress.
"This is clearly an illustration of why we must all work together to fight gun violence in America and keep dangerous weapons out of the hands of the wrong people," said Rep. Carolyn McCarthy (D-Mineola), an advocate of gun control.
Israel says he's good friends with Giffords and her husband and that he had helped her campaign for Congress for the first time in 2006.
"I'm pretty shaken up by this," Israel told Newsday Saturday.
During the 2006 campaign, Israel said, he and his parents, who live in Arizona, joined Giffords and Mark Kelly, a NASA astronaut who is now Giffords' husband, in campaigning in Tucson, with Israel's father driving the car. "Mark said, 'I can survive the space shuttle, but I don't think I can survive your father's driving,' " Israel recalled.
"This is both a personal tragedy and a tragic reminder that we cannot remain silent when political rhetoric turns violent," Israel said in a statement.
He told Newsday: "We just have to learn how to disagree with one another without vilifying one another."
With Will Van Sant,
Tom Brune, James T. Madore and AP