how does the kesubah actually protect a woman?
how much money is the husband supposed to give his wife if they divorce? and how do you enforce it?

Today it's a joke as the couples assets are divided, and the husband is forced to pay alimony and child support regardless of what is or isn't in the Kesuva...

IOW the men get shafted big time.....

If it's large and framed in shatter-proof acrylic it might come in handy... btw, it's either a kesuvah or a ketubah...

I have the opposite opinion.
I have a very good friend who was married for 8 years and has 4 kids when her husband decided he made a mistake. he left her and the kids and won't pay any money to support them. (he went to a country that doesn't have a recipricol agreement with our country)
she had a kesubah and she got shafted. so what good is the kesubah?

Generally speaking, one can usually find an extreme example for anything. I could tell you about my friend who was ordered by the courts to pay her husband alimony (no kids so child support wasn't an issue). You have to look at what typically happens to typical people.

Obviously, back "in the olden days" it did more than nowadays.

1. A Kesuvah is understood only to work in a society and communities where Beis Din has authority.
2. The problem in this case is not the kesuva. The secular courts have no more authority over him than Beis Din because he fled their jurisdiction. There is extremely little that can be done in such a case....
3. The practice was instituted before there WAS a concept of alimony, child support or even life insurance. Back then without a kesuva if a woman got divorced or widowed she was left with NOTHING...