Even the usually wrong Supreme Court judges are very intelligent -- all the better to cloak their legislation in judicial robes -- but retired Justice Sandra Day O'Connor doesn't appear to be the sharpest tool in the shed.

WASHINGTON (CNN) -- Cookies mailed to the U.S. Supreme Court last year contained enough rat poison to kill all nine justices, retired member Sandra Day O'Connor said at a conference last week.

Barbara Joan March, a 60-year-old Connecticut woman, was sentenced last month to 15 years in prison. She sent 14 threatening letters in April 2005 -- each with a baked good or piece of candy laced with rat poison -- to a variety of federal officials: the nine Supreme Court justices; FBI Director Robert Mueller; his deputy; the chief of naval operations; the Air Force chief of staff and the chief of staff of the Army.

March pleaded guilty in March to 14 counts of mailing injurious articles.

March's plea received little public attention until O'Connor discussed it last week.

"Every member of the Supreme Court received a wonderful package of home-baked cookies, and I don't know why, (but) the staff decided to analyze them," the Fort Worth Star-Telegram quoted O'Connor as saying at the legal conference November 10 in the Dallas area. "Each one contained enough poison to kill the entire membership of the court."

O'Connor doesn't know why the staff decided to have the cookies analyzed? Really? The next paragraph:

The letters did not seem to pose much of a real danger since the threatening note told the recipients the food was poisoned. In court papers submitted with the plea agreement, prosecutors said each of the envelopes contained a one-page typewritten letter stating either "I am" or "We are" followed by "going to kill you. This is poisoned."

This just in: if you get some homemade cookies in the mail, accompanied by a note that says "This is poisoned," maybe it would be a good idea not to eat them.

The staff might've done the Republic a service if they'd left the cookies out with the note for judges to consider -- call it an idiot test.