The global conflict of the early 20th century was caused by mainly

The 20th (twentieth) century began on January 1, 1901 (MCMI), and ended on December 31, 2000 (MM).[1] It was the tenth and final century of the 2nd millennium. The 20th century was dominated by significant events that defined the era: Spanish flu pandemic, World War I and World War II, nuclear weapons, nuclear power and space exploration, nationalism and decolonization, the Cold War and post-Cold War conflicts.

what are the issues?

these the citzens and goverment come to terms some of the amendments gave the states more power then the goverment and some protocted americans rights