1996 Mercury Marquis Sloppy steering wheel

I have a 1996 Grand Marquis with 267,000 miles. This is a one owner as I bought it brand new in 1996. There is way too much play in my steering. Seems to be worse since I put on new tires. With the car off, I can move the steering wheel a little left and right. I have heard everything from worn tie rods to steering box. Ny ideas???

By the way, I would donate, but last time I did that, I never even got an answer.

Thanks, Walt