The U.S. Secret Service has serious problems and its director, Julia Pierson, inspired no confidence at yesterday's congressional hearing that she can fix them. She should be fired.

Two dangerous breaches of White House security are enough. Something is horribly wrong in the culture and leadership of the agency responsible for protecting the president of the United States.

On Sept. 19, Omar Gonzalez reportedly scaled the White House fence, ran across the lawn, bolted through an unlocked door, pushed past a Secret Service agent, raced past stairs leading to the family residence and got deep inside the building before he was finally tackled. Gonzalez, a mentally ill Army veteran, had a pocketknife but apparently meant the president no harm. But after he was arrested in July with a sawed-off shotgun, sniper rifles and a map of Washington with a line drawn to the White House, Virginia state troopers warned the Secret Service about him.

In 2011, seven shots from a semiautomatic rifle were fired at the White House. Agents heard the shooting and civilians reported a man firing from his car, but Secret Service officials dismissed the incident as an engine backfiring or random gang gunfire. Four days later, housekeeping staff -- not the Secret Service -- discovered shattered glass inside. Bullets had hit the White House. The discovery led to serious charges against Oscar Ramiro Ortega-Hernandez of Pennsylvania, who is now serving 25 years in prison.

These are examples of potentially tragic incompetence. The security failures were compounded by the Secret Service's lax probe of the 2011 incident and the dissembling since Sept. 19 that misled Homeland Security officials responsible for the agency. And who knows what we don't know? Besides breaches at the White House, there's a new account of how the Secret Service was unaware that a private security guard in Atlanta allowed to enter an elevator with President Barack Obama had a gun and a criminal record.

The Secret Service's reputation for impenetrable protection is in tatters. Fortunately, its problems were uncovered before a tragedy occurred. But the outrageous security lapses could embolden people bent on attacking the country, especially when terrorism is a constant concern. Shamefully, the U.S. Secret Service is not up to the job.