Bicycle Mechanics - Bike won't track straight

I rescued a thrift store bike the other day. It is a joy to ride but the darn thing always runs immediately to the left whenever I try to go without hands. As far as I can tell, the frame is not bent and the wheels run straight and are aligned with each other. What am I missing? Is this a bad thing in the long run?
Thanks

Are the fork legs aligned properly? It doesn't take much mis-alignment to do what you are experiencing.

Are the fork legs aligned properly? It doesn't take much mis-alignment to do what you are experiencing.

Great idea. I did some reading on this. Do you happen to know how I can gauge/correct this without an alignment tool?

I decided to address this as a "thought experiment". Based on my mental deliberations, I'm going to guess and say that if the fork is out of straight alignment, then if you ride in a straight line, one wheel track might be slightly to the left or right of the other. Can you ride through a puddle or something and examine your tracks to see?

I decided to address this as a "thought experiment". Based on my mental deliberations, I'm going to guess and say that if the fork is out of straight alignment, then if you ride in a straight line, one wheel track might be slightly to the left or right of the other. Can you ride through a puddle or something and examine your tracks to see?

Thanks,
I will try to check that tonight.

Thanks,
I will try to check that tonight.
Remember, I'm guessing here, but it makes sense to me!