On October 12, 2001, the junior senator from Wisconsin made the following remarks to the Associated Press Managing Editor's Conference:
We all also had our own initial reactions, and my first and most powerful emotion was a solemn resolve to stop these terrorists. And that remains my principal reaction to these events. But I also quickly realized that two cautions were necessary and I raised them on the Senate floor within one day of the attacks.
The first caution was that we must continue to respect our Constitution and protect our civil liberties in the wake of the attacks. As the chairman of the Constitution Subcommittee of the Judiciary Committee, I recognize this is a different world with different technologies, different issues, and different threats. Yet we must examine every item that is proposed in response to these events to be sure we are not rewarding these terrorists and weakening ourselves by giving up the cherished freedoms that they seek to destroy.
The second caution I issued was a warning against the mistreatment of Arab Americans, Muslim Americans, South Asians, or others in this country. Already, one day after the attacks, we were hearing news reports that misguided anger against people of these backgrounds had led to harassment, violence, and even death. I suppose I was reacting instinctively to the unfolding events in the spirit of the Irish statesman John Philpot Curran, who said: “The condition upon which God hath given liberty to man is eternal vigilance.”
The speech, worth reading in full, was given to explain why Senator Feingold was the only person in the legislature's upper chamber who voted against the USA Patriot Act. In subsequent years, he would be one of 28 Senators to vote against the Iraq War, he introduced a resolution that would've censured President Bush over warrantless wiretapping, he announced his support for same sex marriage, he repeatedly tried to abolish the death penalty, he asserted that Jay Bybee's torture memos were an impeachable offense, he criticized the Bush Administration's detainee policies, and when a person from his own party took the White House, he began criticizing President Obama on wiretapping and excessive claims of executive power.
He wasn't perfect on civil liberties. He is disliked by some libertarians for co-sponsoring the McCain-Feingold campaign finance bill. Whatever one thinks of that, however, he has been among the most consistent and brave voices on civil liberties in the United States Congress, and prescient in opposing some of the worst excesses of America's response to 9/11.