The major increase in the level of federal government spending occurred following the Great Depression, with the New Deal put into place a variety of government programs such as the WPA to help people find employment.
Shows a relationship that does not always indicate cause and effect ,
There were lots of foreign changes that presented challenges for the US. I'll give you a few examples from different time periods. First would be when England wanted to tax the Americans in the Revolutionary period. They did this to try and restrict America's freedom. Another example would be that Russia had spies during the cold war period. This was to gain intelligence of the US war plans. Also when Germany sent the Zimmerman Telegram to Mexico during the WWII period. This was to get Mexico to launch a surprise attack on the US.
The modern Agricultural Revolution was started by the increase in farm technology and new ideas like crop rotation.
Thomas Edison invented the most widely available version of the light bulb. With the advent of AC/DC electricity cities soon began to have streetlights. This would make for a good crime deterrent.
