But, sure, let's ignore what scholars have written on this and meet this question on D'Souza's own chosen ground -- racist Southern Democratic politicians who switched to the GOP.
No, 200 politicians didn't switch -- that's a laughably high bar -- but there were plenty.
1. First and foremost, of course, there's Strom Thurmond, the Dixiecrat presidential candidate, who was welcomed into the GOP in 1964 -- and, importantly, allowed to keep his seniority and thus all the power that came with it in Congress. (No other Southern Democrats were.)
2. But before Thurmond, John Tower left the Democrats in the early 1950s and won election as the first GOP senator in the modern South.
Tower spoke out against civil rights, joined with S. Dems to plot filibusters, and voted against the Civil Rights Act & Voting Rights Act.
The House was quicker to see changes.
3. Rep. William C. Cramer, the first GOP rep in Florida, for instance, switched from the Democrats in 1949, won election in 1954, urged Ike to withdraw troops from Little Rock in 1957 and voted against the Civil Rights Act of 1964.