What key segment of the american electorate did both george wallace and richard nixon try to attract?

Southern "Dixiecrats"--Democrats from southern states were leaving or at the very least unhappy with the Democratic Party and the support of Civil Rights.

George Wallace supported segregation and was able to appeal to southerners who did not like the desegregation policies. Nixon was able to appeal to people who were unhappy with the growing strength of the liberal movement. In both cases it was a draw of white, working class men with nationalistic leanings. 

In my honest opinion , i’d say franklin d roosevelt was a president that impacted our nation , i say this because fdr is voted among top three best us presidents and he was the longest serving president by 3 terms , usually presidents only supposed to have two terms increments of 4 years , equivalent to 8 years total before election time. and he established the fdic , through the 1933 banking act and he established the us , social security system , during his presidency, and established a national minimum wage , through the fair labor standards act , fdr led the allied coalition to victory in wwii and he played a major role in the creation of the united nations.