Story highlights Elizabeth Warren and daughter Amelia Warren Tyagi say it's not building a wall but investing in America's people that will make a difference

They say it took conscious policy to create a strong middle class, we can do it again

Elizabeth Warren, a Democrat, is the senior senator from Massachusetts. Her daughter, Amelia Warren Tyagi, is the co-founder and president of Business Talent Group, a global consulting marketplace, and chairman of Demos, a nonprofit public policy organization. They are the authors of "The Two-Income Trap: Why Middle-Class Parents Are (Still) Going Broke," from which parts of this article are adapted The opinions expressed in this commentary are theirs.

(CNN) America's middle class is starting to crumble.

When we delivered that message in a book called "The Two-Income Trap" back in 2003, it seemed fairly shocking. Today, not so much.

A dozen years ago, if anyone thought about it at all, they seemed to think that America's middle class was pretty close to invulnerable. Solid and invincible — and maybe even a little dull. After all, our middle class had survived wars, scandals, epidemics and a Great Depression. Surely it could survive whatever the 21st century had to throw at us.

Elizabeth Warren

Amelia Warren Tyagi

Even when reports surfaced about rising levels of economic pain, there was a story to explain it — a very comfortable story that made it easier to ignore the bad news. Books, newscasts and breathless five-part series in the local paper came to the same conclusion as your Aunt Edith, the guy in the next office, and pretty much everyone else: Americans are in trouble because they are overspending! Just look at all those Nike sneakers and big-screen TVs. The malls are jam-packed, dog leashes are studded with rhinestones, and everyone — everyone! — has a microwave.

Rising health-care costs? Job insecurity? Climbing foreclosures? (Yes, back in 2003 they were already climbing .) Plug your fingers in your ears, la-la-la I can't hear you. The message was clear: Everything is great. And, if it isn't so great for you personally, then it's your own dang fault.

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