It’s always risky to denounce a proposed security measure as excessive — the risk is that the measure is not implemented and a disastrous terrorist attack ensues. But we don’t mind saying the proposal to scan passengers on the Staten Island ferry strikes us as excessive, a view shared by a number of important residents of Richmond. “I can only imagine what it would do to a daily commute,” said Rep. Vito Fossella, the Republican who represents Staten Island in Congress. “I would hope that common sense would dictate here.” The chairwoman of the Ferry Riders Committee of the St. George Civic Association, Tamara Coombs, was also skeptical in a phone interview with our Matthew Sweeney. As it is, the New York Police Department does a fine job of keeping the ferry safe. The last thing New York needs is Washington telling the NYPD how to protect New Yorkers. The Maritime Transportation Security Act of 2002, the law that the Coast Guard may use to require such screening, included no language requiring such measures. Imposing them would be a leap of legislation by regulation. There may be some passenger vessels where metal detectors are appropriate — tourist ships bound for the Statue of Liberty or other high-profile potential targets, for example. But the Staten Island Ferry isn’t one of them. Imposing a nationwide standard on all ferries is exactly the sort of thing that makes Americans recoil at the emphasis on homeland security. It’s far preferable to fight the terrorist enemy on their seas and soil.