I would argue that the United States does not need to take steps to address overpopulation at this point. There are two major reasons for this.
First, we are not experiencing rapid population growth through natural increase. Our fertility rate is at an all-time low and we are barely at replacement level. Most of our population gain is through immigration. If we prohibit immigration, we will reduce population growth in the US, but will not do anything to reduce overpopulation of the world as a whole. Thus, instituting population policies in the US would not really help the world.
Second, overpopulation only exists relative to resources. At the present time, most of our resources are not overstretched. We have plenty of food for everyone in the US. We still have plenty of room. Most parts of the US have enough water for everyone. In that sense, we are not overpopulated. It would make more sense for us to work on ways to conserve the resources we have rather than to try to reduce our population.
For these reasons, I do not see overpopulation as a real problem in the US.