As one of the surviving members of the staff of the Warren Commission, which investigated and issued a report on the assassination of President John F. Kennedy, I am not looking forward to the coming weeks: Nov. 22 will mark the 50th anniversary, and that means a new round of demonizing the Warren Commission and celebrating conspiracy theories.

The evidence that Lee Harvey Oswald killed the president was overwhelming. We reviewed ballistics analysis, medical records, eyewitness reports, acoustic patterns and a host of other records and investigative reports, all of which demonstrated beyond doubt that Oswald was the assassin. Scientific evidence confirmed that all the shots fired came from where Oswald was perched and the gun belonged to him. He showed consciousness of guilt by fleeing and killing a policeman. It wasn’t the first time Oswald had contemplated assassinating someone. He had tried to kill a former Army general prior to shooting the president.

One reason the conspiracies gained such hold was the bizarre second act of the assassination story, in which strip club owner Jack Ruby shot and killed Oswald as he was being moved by police two days after Kennedy’s assassination. Another factor that fueled the conspiracies was the odd histories of both men. Oswald had lived for a time in the Soviet Union and attempted to renounce his American citizenship. Ruby had an arrest record but had friendly contacts with the police.

But nothing in our extensive investigation of the contacts, finances and activities of Oswald and Ruby, including reviews of information from domestic and foreign intelligence sources, indicated a conspiracy. Nor has any credible conspiracy arisen in the 50 years thereafter.

If Oswald’s estranged wife had not, on the night before Kennedy was shot, rejected her husband’s offer to reconcile and look for an apartment the next day, there would have been no assassination. And if a last-minute interrogation of Oswald had not delayed his transfer, Ruby would not have been at the jail in time to kill Oswald. These unfortunate coincidences are not consistent with a conspiracy.

Conspiracy theorists have often attempted to latch on to some inconsistency with the commission’s findings. One has to view the totality of the evidence in order to draw the most reasonable conclusion.

The Warren Commission staff was composed primarily of highly regarded lawyers from around the country with an array of political views. I was a young, soon-to-be private-sector attorney. My father, then California’s attorney general, was an early supporter and political confidant of Kennedy. I had the privilege of meeting Kennedy when I was an undergraduate at Stanford, and I had every incentive to find and expose a conspiracy if one existed. With a top-secret security clearance, I had full access to the work of the staff, and I never saw anything untoward.

The simple explanation that a troubled but powerless person brought down the world’s most powerful leader just doesn’t seem sufficient.That’s why it was important for the Warren Commission to investigate and to release its 888-page report with 26 volumes of supporting material. The investigation includes more than 25,000 interview reports and information from many agencies. It might still stand as the most extensive and thorough criminal investigation in history.

Those who, after almost five decades, contend that some information was withheld from the commission or that it did not follow matters to the point of certainty, even if true, have not been able effectively to show that these alleged deficiencies could have affected the conclusion. The issue should not be whether the commission reached perfection in its methodology but whether the evidence supports its conclusion. And it does.

The history books now seem reconciled to the fact that Oswald, acting alone, assassinated the president. I hope on this 50th anniversary, the public will be skeptical of new criticisms of the commission and more doubtful of the new conspiracy theories than of the Warren Commission.