The new law should allow more disabled people to enter the mainstream of American life.
Could you explain it to me what "mainstream of American life" means here?
It means that disabled/handicapped people will be able to go out and about to the same places and enjoy the same activities as the able-bodied/non-handicapped.
For example, the Americans with Disabilities Law makes it mandatory in the US that all public transportation (buses, trains, subways) be wheelchair-accessible. ATM machines, elevators, and other such devices have instructions printed in Braille. Walk/Don't Walk crossings at very busy intersections have audible chirps and buzzers to alert the blind that the light is green. Public buildings have wheelchair ramps. Television sets have built-in closed captioning ability. A certain percentage of rooms in each hotel must be equipped with handicapped-accessible shower stalls. Etc, etc.