Maternity Leave Policies in the U.S.

Why is the U.S. one of the only countries in the world that doesn't legally require businesses to offer paid maternity leave? This wasn't an issue I was even aware of until I got pregnant--for some reason I assumed that in America, we had paid maternity leave--but today I watched a John Oliver segment about family leave and learned that I was wrong! U.S. law requires large businesses to provide 12 weeks of unpaid maternity leave, and there may be additional limitations on top of that (e.g. working with a company for at least a year before you're entitled to it, etc.) I'm appalled and also now really concerned about our own situation. My husband's in the Army, and I'm currently a stay at home wife, but soon, my husband's time in the Army will be coming to an end and all of that will be changing. We'll be moving back to our home state and looking for new jobs--while I'm 3-4 months pregnant. Already I was worried about finding a job and about disclosing my pregnancy, but now I'm also worried about maternity leave... will I still be eligible for it as a new employee? Will I be able to find something with paid maternity leave? What if I can't? Will I have to go back to work the day after pushing a tiny human out my hoo-hah? That would break my heart. When we move, I won't be able to do the stay at home thing anymore, we won't be able to afford it. And all of our savings will likely go toward our move and our first month of living expenses. There's no way we'll be able to build it back up to 3 months worth of living expenses before the baby is born. I'm so fucking anxious. I wish we could just move to Canada. *sigh* Anyone else have experience with/advice for looking for/getting a new job while pregnant?