Police in New York and Washington are on high alert - and visibly so - in advance of Sunday's tenth anniversary of the Sept. 11, 2001 terrorist attacks, though there was little new detail about a reported threat of a truck- or car-bomb attack plot timed to coincide with the anniversary.

Police are making a show of force in New York, The New York Times reports, with stepped up patrols on land and water, all intended to heighten vigilance toward what was described as a "very, very sketchy" tip that a plot is in the offing. How sketchy?

From The Times:

Officials briefed on the threat offered varying views of how serious it was, and some suggested that the strong reaction from federal and local agencies reflected heightened wariness around the anniversary. The two senior law enforcement officials, who were not authorized to speak publicly about the investigation, were in the skeptical camp.

“It’s 9/11, baby,” one official said.  “We have to have something to get spun up about.” The second official said the reported plot “could all be one big fabrication, but no one wants to take any chances.”

Another official acknowledged that the tip could turn out to be wrong. But the imminent anniversary did not allow much of a window to study its veracity.

“There was no time to sit around and think it over,” the official said. “The appropriate thing to do it is to share the information and provide proper warning.”

The Associated Press and NBC News reported that the possible attackers could be American men, presumably making it easier for them to enter the country. The tightening of security was not scaring off pedestrians and passersby in Lower Manhattan or New York, the AP reported

Undaunted by talk of a new terror threat, New Yorkers and Washingtonians wove among police armed with assault rifles and waited with varying degrees of patience at security checkpoints Friday.

Security worker Eric Martinez wore a pin depicting the twin towers on his lapel as he headed to work in lower Manhattan where he also worked 10 years ago when the towers came down. "If you're going to be afraid, you're just going to stay home," he said.

New York Mayor Michael Bloomberg took the subway to work Friday, AP also reported.

The sudden uptick in visible security measures could be the most appropriate memorial of all to the events of one decade ago, or so goes Kevin Drum's argument. Here's his reflection on the vast new security apparatus the nation has created over ten years, and the wary attitude toward potential threats from a country that once allowed citizens to stroll into the Pentagon without so much as a metal detector screening.

This is, for me, the most enduring legacy of 9/11. I imagine the wars will all be over eventually, Al Qaeda will be conclusively dismembered, and even the drones might be put back in their hangars. But the protective apparatus we've put in place, both the less visible surveillance state and the highly visible security state, will be with us forever. And they'll get worse and worse: If the past decade is any judge, Americans seem willing to put up with an almost unlimited amount of this stuff as long as it's done in the name of protecting us from terrorism.

Update: If the new plot sounds similar to the attempted car-bombing of Times Square last year, there's good reason for that, The Daily reports:

A highly placed source in the federal government noted that the details of the current threat are “eerily similar” to Faisal Shahzad’s failed attempt to detonate an SUV filled with explosives in Times Square last year.

Both plots involved vehicle-borne improvised explosive devices and chemicals. And intelligence officials are looking into the possibility that some of the suspects said to be aiding three operatives planning a 9/11 anniversary attack received training at the same camp in Pakistan as Shahzad, according to a government source familiar with the investigation.