Landslide victories do not guarantee that Congress will be of the same party and therefore can prevent continued success by the President.
These presidents were reelected due to the trust Americans had in them to get the country through a tough time. FDR--Great Depression, LBJ--assassination of JFK, Nixon--Vietnam/activism, and Reagan--recession. However, Congress was not in their favor to continue the policies they had been using in their first terms. On that note, these were all 2nd term (LBJ was technically first election but had served two years already) elections where the president had gained the approval of the people.
All faced increased adversity as well after the landslide victory. FDR--recession and WWII begins, LBJ--entry into Vietnam, Nixon--Watergate, and Reagan--stock market crash.
The battle of fort sumpter is said to be one of the first signs to the start of the American civil war
I think that the answer is 12. hope this helped! ^^
