The ongoing controversy about a security breach at the White House — a scandal that’s led to the resignation of the head of the Secret Service — made us think of a simpler time when access to the president’s residence was a lot looser.

In “Washington Goes to War,” his 1988 book about how World War II transformed the nation’s capitol, the late journalist David Brinkley recalled what life at 1600 Pennsylvania Ave. was like before the war.

“It was still possible in 1941 to walk through the White House gate and into the grounds without showing a pass or answering any questions, since the White House was not yet considered much different from any other public building in the city,” Brinkley told readers. “Until a few years before there had been no gates at all, and on summer days, government employees had lounged on the White House lawns eating picnic lunches out of paper sacks.

“In the mid-thirties, a Washington resident was driving his Ford convertible down Pennsylvania Avenue with the top down when it began to rain. He turned into the White House driveway and drove under the portico for shelter, put his top up, and went on. Only 25 years before that, in (William Howard) Taft’s administration, tourists looking around inside the White House had been allowed, when the president was absent, to go into his office and sit for a moment and bounce in his chair. It was all casual, easy, open and trusting.”

Since then, of course, the security perimeter at the White House has gotten bigger, the access tighter, all in acknowledgment of a world where terrorism looms more vividly. The recent lapses in White House security seem all the more unthinkable given our high expectations of how secure 1600 Pennsylvania Ave. should be.

Those expectations are a relatively new reality in America’s history, as Brinkley’s book reminds us.

The current controversy surrounding security at the presidential residence will bring a lot of scrutiny to bear on the measures now in place to protect the president, his family and his inner circle.

One thing seems certain, though. The days of casually lunching on the White House lawn without an official invitation, or driving at the spur of the moment up the White House gates without causing a stir, or poking around the president’s office while tour guides look on — those days, we’re sure, are never coming back.