The United States military campaign against Iraq reverberated last week throughout Southern Maryland, where police and federal officials ratcheted security up another notch, emergency responders planned for a terrorist attack and residents passionately debated the wisdom of a preemptive war.

Security was tightened at Calvert Cliffs Nuclear Power Plant, where officials have canceled all tours. In addition to the plant's own security personnel, a Maryland State Police trooper is assigned to guard the plant 24 hours a day, a precaution that also was taken after the terrorist attacks of Sept. 11, 2001, said Lt. Homer Rich, commander of the Prince Frederick Barrack of the Maryland State Police.

State troopers and Calvert sheriff's deputies are making routine patrols around the power plant and other locations, officials said. More troopers are on the road, and they are working longer hours, Rich said.

"We're doing patrol checks like there is no tomorrow," he said.

The U.S. Coast Guard increased patrols along Southern Maryland's waterways, and federal authorities warned recreational boaters to stay away from the Coast Guard boats or risk being prosecuted. The Coast Guard said it was making checks at the Calvert Cliffs plant and the liquefied natural gas plant at Cove Point, Patuxent River Naval Air Station in St. Mary's County and the Naval Surface Warfare Center in Indian Head.

Those institutions are considered the area's most likely terrorist targets, though authorities said the chance of such an attack in Southern Maryland is relatively low.

Officials at the local Navy bases would not comment on the security measures they have taken. So far, the bases have not instituted a measure taken after Sept. 11 -- that of searching every employee who comes on base. A year and a half ago, the measures caused traffic problems in Lexington Park and Indian Head.

"We will be making every effort possible to reduce traffic congestion" if such a measure is taken, said Chris Adams, a spokeswoman for the Indian Head base.

Law enforcement officials said additional scrutiny was also being paid to area hospitals and bridges. In St. Mary's, bomb-sniffing dogs and their handlers made sweeps around water supplies and utilities, said Sheriff David D. Zylak (D), and other sheriff's offices said their canine teams are on alert.

Law enforcement officials said the added homeland security duties will not diminish the police presence in neighborhoods. Zylak said that could change if the federal terrorist threat level is increased from orange, or "high," to red, or "severe."

Local emergency management officials began readying response and evacuation plans in case of a terrorist attack. A tri-county homeland security plan calls for each jurisdiction to focus on a different aspect of counter-terrorism measures -- Charles is responsible for planning for a chemical weapons attack, St. Mary's for biological weapons, and Calvert for a release of dangerous radiation from Calvert Cliffs.

Charles County may be an important receiving point for residents who may have to evacuate Washington in the event of an attack, said Don McGuire, Charles County emergency management director. He said plans are in place for area schools -- if they are not in session -- to be set up as shelters.

And so there is little to do now but wait.

"We're kind of in the same boat as everybody else -- sitting back and watching," said Donald Hall, Calvert's emergency management director.

The progress of the war in Iraq is watched closely by many in Southern Maryland, which is typical of the Washington area in that many of its residents are retired or active military personnel.

"This is a military community," said J. Frank Raley, senior vice president of the Navy Alliance, a St. Mary's coalition of business owners and defense contractors. "People have a professional interest in what's going on."

At the Naval Surface Warfare Center in Indian Head, employees watched as high-tech weapons they helped test and design were used in combat for the first time. Adams said such weapons include a new version of the Tomahawk cruise missiles, known colloquially as "bunker busters." About 40 of the Tomahawks were fired at sites in Baghdad on Wednesday night at houses where Hussein and his two sons were believed to be, according to news reports.

"We're very proud of the direct contributions we are making to the war effort," Adams said.

Bar patrons at the Crossing at Casey Jones in La Plata saw and heard those missiles explode in Baghdad on cable television. And between sips of beer and shots of whiskey, they debated the wisdom of this war.

"Iraq is a threat and people can't walk around looking over their shoulders. You have to get rid of the threat," said Paul Simmons, 43, a D.C. police officer from La Plata.

"I'm against it. I think North Korea is more of a problem," said a man sitting near him who declined to give his name.

At the other end of the bar, Craig Howard, 35, said he did not want war but he also did not want to risk more attacks like those on 9/11. Howard's friend, Laura Leslie, said she had "mixed feelings" about military action. The world's problems have created some absurd situations here at home, she said, like when she heard a child ask his father about a burglar alarm at the St. Charles Towne Center.

" 'Was that a burglar alarm? I thought North Korea had come and nuked us,' " Leslie said the father answered. "And he's saying this to an 8-year-old child.

"I think what's going to hurt us most is mass hysteria."

Staff writers Theola Labbe and Eugene L. Meyer contributed to this report.