Dear Dr. Ben Carson:

Congratulations on your nomination to be the next secretary of the Department of Housing and Urban Development.

You may know everything about housing. Maybe you only know a little. Either way, there will be a long line of people telling you exactly what you should do. Some of their advice will be political. Some of it practical. May you always know the difference. And in your position there will be difficult decisions ahead—ones that affect hundreds of thousand, even millions, of lives. May you always choose to help the most people and the neediest.

There are countless men and women who know much more than I do, but I know this much to be true:

• There’s no county in the United States where a full-time minimum-wage worker can afford a basic two-bedroom apartment. Not a damn one;

• The number of renters (paying more than 30% of their income for housing hit a record 21.3 million in 2014. More than half of these renters—11.4 million households—were severely burdened (paying more than 50% of their income for housing); and

• Nearly 550,000 people were experiencing homelessness on a single night this year. That’s a ton of people, but the number has been falling—14% since 2010. It’s progress that needs to continue. No retreat. It would be a shame to lose any ground that’s been made.

I also know that if you visit a few good low-income housing tax credit properties, you will be impressed by the housing that’s being built and the people who live in them. Fair warning: These visits have turned skeptics into evangelists for the nation’s most important tool to build and rehabilitate affordable housing.

I know that discrimination still exists, and that means so must strong fair housing laws.

I believe that affordable housing is like an iceberg. You see the home, but there’s much more below the surface. It’s the foundation that provides good health, allows children to succeed in school, and people to access jobs. If you get housing right, you’ll get a lot of other things right.

And, finally, I know that HUD needs a fighter. People have said the agency needs a housing expert or it needs an outsider. No, it needs someone to protect, improve, and expand housing policies and programs. The secretary needs to be the first to shout from the rooftops that the nation is in a housing crisis. The HUD secretary needs to stand up for housing and all the people HUD serves.

That I know is true.