One hint came from a video for the very brief official opening of the convention, which saw him looking noble over lines about the US being built on on immigration and diversity.
Phasing out immigration quotas could help promote ethnic diversity and have an unintended consequence of undermining the political consensus for entitlements.
During the mid-19th century, Maryland was a major immigration center, and its ethnic diversity (Maryland has a higher percentage of black residents -- 25 percent -- than any state outside the South) still sets it apart from many Southern regions.
In order to free up those green cards, the legislation eliminates the Diversity Immigrant Visa Program which sets aside visas for countries with low rates of immigration to the United States.