In the United States, people are mostly free to buy or rent property in whatever place they choose, subject to their resource constraints. This is because the U.S. is mostly a free country and this is mostly a good thing.
This statement is less true with respect to poor people. Housing providers more often turn poor people away from housing they could afford because of discrimination. This problem is exacerbated by gentrification, especially when poor people are pushed out of their communities because their landlords stop accepting their Section 8 vouchers. And because poverty is correlated with race in this country, this results in minority communities being pushed out due to gentrification.
This problem can be addressed on a national level by amending the Fair Housing Act (“FHA”) to include source of income as a protected category. It can also be addressed piecemeal by state law, but as of 2013, only 13 states have passed fair housing laws that include source of income as a protected category. National Fair Housing Alliance 2013 Fair Housing Trends Report, p. 8. (The entire report can be accessed here: http://www.nationalfairhousing.org/LinkClick.aspx?fileticket=rJOodoEJhG4%3d&tabid=3917&mid=5321) Unfortunately, in some of those states, while SSDI, unemployment benefits, and trust funds are included as protected “sources of income” under the law, Section 8 is not, because Section 8 vouchers are paid directly to housing agencies or landlords, rather than to the tenants. See e.g., Sabi v. Sterling, 183 Cal. App. 4th 916 (2010).
Gentrification is essentially an economic phenomenon and it will happen by the force of the invisible hand. But, one advantage of living in the United States in 2013 is that these trends can be documented and analyzed in concrete numbers as they are happening. The negative externalities of gentrification can then be quantified and discussed by the communities that they affect. If the effects are bad enough, the communities may mobilize and address these issues through political action, such as amendments to state fair housing laws. And if these state efforts get enough traction, they may even lead Congress to amend the FHA.