The late great Larry Saegers (sp?), former Utah State Horticulturist helped me out a great deal.
If in your grass, spray it with liquid weed and feed everytime you see it. This will may not get rid of it entirely, but will control it (and I found often does get rid of it after a few years).
If in garden, Round up everytime you see it.
The roots can go as deep as 20′ and if you break the root, new plants will start from every broken root. So yea, DON’T pull it.
I keep both products in pressue sprayers. Everytime I mow I will watch for it. If i see any, I immediately spray it. I still have some in my yard, but no one would ever know but me.