We need to get our own planet's managements in order, such as health-care, world hunger, and homelessness first. Plus if something goes wrong, we will have just wasted billions of dollars. (P.S., we will never live on Mars. Period.)
We still are not sure if it would be possible to put breathable air into mars' atmosphere. If we fail, do you know how many billions of dollars we have just wasted? plus, there is no water on mars, so therefore it is still unable to sustain life. Further more, humans are made to adjust, so if we need to adjust ourselves to an over populated planet, so be it. plus, new laws are being put into place in the over crowded regions of the world.
I agree with the comment, "Laws will take away our freedoms". I give my opponent that we are made to adjust but our bodies can only take so much. As for the fact that there is no water, water can be imported along with air. We could allow a small poplation to live in a dome.