You can't there is no such thing as "free energy".

by signing the Sussex Pledge

Measures backed by the Coolidge administration include Immigration Act of 1924, Merchant Marine Act, The Young Plan, and US-Nicaraguan relations. The immigration act reduced the number of Southern and Eastern Europeans entering the US. The Merchant Marine Act encouraged American ship-builders through a federal loan program. The Young Plan refashioned German reparations formula. Relations with Nicaragua preserved stability and American investments in the area.

The Triple Alliance was Germany, Austria-Hungary, and (nominally) Italy. Italy basically didn't do much of anything (except see who was offering the better deal) for about a year, then broke off to join the war on the opposing side.

Many people were opposed to Wilson's 14,points, Americans and other world leaders alike. Some of the reasons they were opposed to it were that they didn't like the League of Nations and the wide ranged idealism of the whole thing.

Man-Elkins Act

Allied naval blockade of German ports were causing hardship to German citizens and hampering Germany's war effort. However, from the various naval battles with the Royal Navy, the Imperial German Navy had learned that it can not defeat the Allied on surface battle. Hence the aims of lifting Allied naval blockade on German ports and crippling the shipping bloodline of British Empire can not be achieved without the use of submarines. However, normal submarine warfare where U-boats have to surface and reveal its presence before searching and attacking is deemed to be too cumbersome, hence the use of unrestricted submarine warfare.

The 4 countries of the Central Powers were Germany, Italy, Austria, and Hungary (but note that at the time, Austria and Hungary were part of what was known as the Austro-Hungarian Empire).

Basically, since the invention and more widespread use of the submarine, there were certain rules of warfare regarding them. Submarines, when they wanted to sink a ship (when it wasn't an obvious military ship), were supposed to pop up out of the water so that the ship could see them; then someone from the submarine was expected to tell the ship that the submarine was going to sink it. The submarine had to give the other ship time to evacuate the crew to lifeboats and get a safe distance away. Once all that was done, the submarine was allowed to sink it.

Obviously, that doesn't work well when you want to get stuff done fast. Germany's navy was far smaller and weaker than Britain's; throw in France's and those of other countries, and Germany was at a considerable disadvantage. Germany needed to be able to hit hard and fast without having to slow down if they wanted to have any chance at defeating the Allied navies.

So unrestricted warfare was basically ignoring those old-fashioned rules. They began sinking ships without warning, meaning crewmen were getting killed, and the whole ship was lost. German subs would sometimes accidentally shoot neutral ships, like those belonging to the US, or shoot ships carrying people from neutral countries (like the British cruise ship, the HMS Lusitania, which had over 100 Americans on board when the Germans sank it).

Germany agreed to stop unrestricted submarine warfare after the Lusitania incident, because they didn't want the US to join the Allies. But in early 1917, they decided that they couldn't keep that up, and had to restart it. This, coupled with their attempt to secretly convince Mexico to declare war on the US, angered the Americans enough that they declared war on Germany in April 1917.