Link? I'm seeing not 53% but more like 50.7%Lyndon Johnson and FDR were the recent ("within my lifetime") Democrats to win 53% of the vote. I think that among Republicans Reagan, Nixon, and Eisenhower all did it.
Even at 50.73%, Bush won with a higher percentage of the popular vote than any Democrat president except Lyndon Johnson, Franklin Roosevelt and Andrew Jackson. Most Democrat presidents have won with a plurality.
In contrast, every Republican president in the 20th century broke 51% at least once (Bush Sr., Reagan, Nixon, Eisenhower, Hoover, Coolidge, Harding, Taft, Theodore Roosevelt and McKinley). Reagan, Nixon, Eisenhower, Hoover, Harding and Theodore Roosevelt all broke 55%.