Let's not pretend anymore that the tea party movement is harmless. The right to protest is one of our cherished American freedoms. But there is no right to vandalism, no right to threaten our elected officials' lives. Someone is going to get hurt unless those who lead the movement — and those who exploit it — start acting like responsible adults.

What are the chances of that?

It was Sarah Palin, the Eva Peron of the tea party crowd, who used Facebook to target 20 Democrats who voted for health care reform, indicating their districts' locations on a map with the cross hairs of a rifle scope. It was Palin who wrote on Twitter: "Commonsense Conservatives & lovers of America: 'Don't Retreat, Instead — RELOAD!' Pls see my Facebook page."

That anyone still listens to this person is one of the most unfortunate unintended consequences of social networking.

At least 10 House Democrats have had to request additional security following Sunday's health care vote. Someone left a coffin on the lawn of Rep. Russ Carnahan's home in Missouri. Glass doors and windows were broken at the district offices of Reps. Louise Slaughter of New York and Gabrielle Giffords of Arizona. Vandals have damaged Democratic Party offices in Wichita, Rochester, N.Y., and Cincinnati.

And Rep. Bart Stupak of Michigan, whose last-minute compromise on abortion funding guaranteed final passage of the reform act, has received a flood of abusive phone calls at his office and home. Someone faxed him a drawing of a noose. One voice mail, subsequently posted on the Internet, was left by a woman who wanted Stupak to know that "there are millions of people across the country who wish you ill." Another caller was more direct: "You're dead. We know where you live. We'll get you."

One would expect responsible Republican leaders to do everything in their power to lower the temperature. House Minority Leader John Boehner said on Fox News that "violence and threats are unacceptable." Minority Whip Eric Cantor disclosed that he has received numerous threats in the past and that a bullet was fired through the window of his Richmond campaign office last week. Given all this, one would think these two might have intervened Sunday when fellow House Republicans were whipping up the angry tea party crowd at the Capitol.

Some of the vandalism appears to have been inspired by an Alabama blogger, Mike Vanderboegh, who trumpeted the bright idea that opponents of health care reform should throw bricks at Democratic headquarters across the country. After someone did just that in Rochester, a reporter from the Democrat and Chronicle called Vanderboegh for comment. "I guess that guy's one of ours," Vanderboegh said. "Glad to know people read my blog."

Yesterday, tea party leaders around the country issued statements strongly denouncing threats or violence against members of Congress or anyone else. A number of the leaders said there was no proof that the perpetrators were members of tea party organizations.

But this strikes me, and probably will strike others, as disingenuous. The tea party movement is fueled by rhetoric that echoes the paranoid ravings of the most extreme right-wing nutcases. When tea party leaders talk about the threat of "socialism" and call for "a new revolution" and vow to "take our country back," they can say they are simply using vivid metaphors. But they cannot plausibly claim to be unaware that there are people — perhaps on the fringe of the movement, but close enough — who give every sign of taking these incendiary words literally.

And does anyone doubt that the movement attracts the kind of people who take these words literally?

Organizations such as the Anti-Defamation League and the Southern Poverty Law Center have documented the troubling rise of right-wing militia and "patriot" groups. Political leaders who appropriate and reinforce the extremists' language — who urge angry people to "reload" — are being reckless. They must stop this madness before someone gets hurt.