RPWontBackDown...the truth is on your side...it's just that the history books have been written by the victors so there is very little information out there that paints US involvement in WWII as negative.
The WW1 argument is not a bad tact...but probably insufficient for most. It will be important to bring up how it was so unwise to for the allies to issue such harsh penalties on Germany. Germany lost a lot of land (with native Germany speakers) to neighboring countries. In fact it was split in two by a land corridor for Poland to allow Poland to have access to the Sea...very convoluted. Then Germany faced immense economic debts that was only really fixable with hyperinflation. This ruined the Germany economy and absolutely destituted it's people. There were other factors as well like embargos that didn't help and a minor communist civil war supported by the Soviet Union that aggregated the situation..granted Germany is not a saint in all this, but the manner in which they were treated was most unwise.
A more effective argument would be to argue that we should not have been supporting the Stalin and Mao...and that they killed millions of their citizens and were monsters that should not have been supported with American money and lives.
The most effective, but most complicated tactic would be to argue the details of the war.
Start with US vs Japan...as that will be easier to convince on.
There are tons of quotes out there from FDR where he talks about trying to get a war started with Japan by having them fire the first shot:
eg how we should maneuver them [the Japanese] into the position of firing the first shot without allowing too much danger to ourselves
Motive was very clear. One of many quotes. You can also talk about how Japan at the time had no colonies...while the US had plenty of Pacific colonies (conquests from the Spanish/American war) and China was a land mass that indirectly qualified as a colonizing power (like their bullying of Tibet). Then you can talk about one of many goading techniques the US used. One of the most inflammatory techniques (outside of the embargo) was the Hull note...which was basically do all of our bullet points or face war. Among the bullet points was:
The Government of Japan will withdraw all military, naval, air and police forces from China and from Indochina.
...of course no provision for the US to get out of the Philippines or other Pacific colonies.
Japan felt with this and other signals from the US that war was inevitable. So they felt...if the US is going to attack us...why not get the advantage of the first move? Hence Pearl Harbor which the US government had more than an inkling would happen (plenty of info available on google). The US government was quite racists at the time and probably didn't expect Asians to be competent enough to inflict much damage onto western militaries hardened from WW1.
The war itself could have been wrapped up a lot earlier. The Japanese repeatedly wanted a peace treaty but the US demanded unconditional surrender. In fact just prior to the US dropping the a-bombs, the Japanese had offered a nearly complete surrender...with just an exception kept to protect their god/emperor. So the official story that it was 'either a massive land invasion' or 'drop the a-bombs' is a lie. An accurate retelling of history clearly shows had the US government had the will...war with Japan would have been easy to avoid.
In regards to Germany... First one needs to realize that the US had already been operating a covert war against Germany prior to the Pearl Harbor. They had been sinking Germany subs, engaging in other covert operations and suppling arms to Britain. Hitler noted this in his declaration of War against the US when it was brought into the war with its treaty with Japan (which FDR had been quoted as banking on). The entire German war was easy to avoid. Let's start with Poland...everybody is outraged when Germany moved in...but what about the Soviet Union? Why do they get no blame? With Germany they claimed German natives were being mistreated by Polish citizens...this could have been the truth. The situation is a tricky one though as the Polish/German borders were artificially constructed ...especially the land corridor that split Germany. Granted Germany acted badly in taking over several of their neighboring countries...but history isn't completely black and white on this...and there were many complicated territorial/political/and cultural issues that were factors that aren't discussed today.
England and France declared war on Germany...not vice versa. Germany did not want war with England...and Hitler actually spoke well of the British. The Germans would repeatedly offer peace treaties to the British but warmonger Churchill wanted his total war. In fact, Germany's #3 most powerful man, Hess in 1941 flew to Scotland to seal a peace treaty with Great Britian (specially with the Duke of Hamilton), but the Churchil locked him up and refused to let anybody talk to him.
Much has been made of the deaths of the Jews...which was a travesty...but there is more to the story. The concentration camps started out as industrials jails mostly aimed against the communist with whom Germany had a minor civil war with. There just wasn't enough jail space with the old jails. Certainly Germany wasn't alone in having them... the US had them for the Japanese and the Brits are sometimes credited with creating the concept. Yes, many executions took place (the allies including the US and Britian also killed prisoners...but not in that scale...unless you count China/Soviet Union). The main cause of death was neglect though. The prisoners weren't fed adequately or lacked proper medical care and sanitation which resulted in mass starvation and disease. The deaths of the prisoners didn't really take off though until the end of the war. In many ways ironically the bombing of Germany infrastructure exaggerated the situation as this resulted in massive food shortages. Troops on the eastern front were starving, so it was difficult politically to justify feeding prisoners over soldiers. It is safe to say that had the Germany attained peace earlier a lot of political prisoners would not have died (many Jews but perhaps as many or if not more communists).
The bottom line was that peace was available...all the US had to do was to want it. Instead they exaggerated a situation Europe should have settled on its own and created two monsters in the Soviet Union and Red China. The real history is certainly not what the warmongers want you to know...they're quite proud of the WW2 as their model 'just war' that in turn justifies many other 'just wars'. Be ready, if you challenge any of the official accounts of WW2 and dare suggest peace was the best option...to be viciously attacked. You'll be called naive, an anti-semite and worse. Yet the truth is on your side though...