ASMALL FLEET OF television satellite trucks was parked across the street from World Bank headquarters yesterday. On 19th Street NW, police were pulling over trucks headed in the direction of the International Monetary Fund, demanding credentials from drivers. Police milled around the entrances to both buildings, which were on a list of potential targets enumerated Sunday by Homeland Security Secretary Tom Ridge, along with the New York Stock Exchange and Citigroup headquarters in Manhattan, and the Prudential building in Newark. But all of this activity, soothing though it may be to the people who work in those buildings, underlines the difficulty that surrounds Mr. Ridge's security warning, even one as detailed as this.

For although this latest information pointed to precise targets, only a broad time frame was supplied. Some of the information reportedly in al Qaeda's possession, on the structure of the buildings and their security, had been collected over a period of years. World Bank President James D. Wolfensohn told his colleagues yesterday that "there is no information that indicates a specific time for these attacks." Hence the odd sight of police pulling trucks over, as if attacks were imminent, and journalists parking their trucks directly in front of the buildings, as if attacks were only theoretical. A District government spokesman grumbled that naming places "gives it a little more specificity, but obviously not enough."

The ambiguity makes advice to those who work near the listed targets less clear than anyone would like: Go to work as normal -- a suggestion IMF and World Bank employees appeared to be following yesterday -- but be alert for unusual cars, trucks, people or packages. Other commuters, both on Metro and in traffic, are advised to do the same. Over time, officials say, new security procedures in the target areas will be made permanent, but in the meantime, pedestrians and drivers will be subjected to unexpected inconveniences, such as closed streets and police checks.

Precisely because it can create confusion, the ambiguity makes politicians' treatment of these warnings, now and in future, extremely sensitive. It is important that prominent Democrats such as former governor Howard Dean refrain from observing, as Mr. Dean did, that "every time something happens that's not good for President Bush, he plays this trump card, which is terrorism," because that would imply that no terrorist threats, however serious, should be taken as such. It is equally important that the administration not politicize its warnings, because to do so would weaken them.

In his statement, Mr. Ridge stayed away from politics, although he did, as in the past, find it necessary to attach a list of his homeland security achievements along with the warning, which did reduce its impact. The administration's decision to brief the Democratic presidential contender, Sen. John Kerry, probably helped dampen partisan feelings. Both sides should remember that everyone who lives and works in Washington, New York and Newark will benefit from these warnings only if everyone involved bends over backward to depoliticize this issue in a political season.