It had only been 20 odd years since the last world war. Most of the people alive then knew first hand what horrors the war produced. Neither Britain or France had the stomach for another costly war. You'll note also that the Americans were vociferous about not getting drawn in to another European conflict.
The Allies had forced harsh reparations on Germany after the first world war and Germany's economy was stagnating and the German mark was worth next to nothing due to rampant inflation. They had nothing to lose, and when a demagogue arose to seize power, because of the complacency of Germany's then current leaders and the population in general; it was inevitable that another conflict would ensue.
Churchill said it best, "Either you keep the Hun under your foot, or he'll be at your throat!"
Britain and France on 3rd September 1939 and Poland 2 days before on 1st September
Britain and France
The Triple Entente (from French entente, "agreement") was the name given to the loose alignment of Great Britain, France, and Russia after the signing of the Anglo- Russian Entente in 1907.
They waited before invading France
Great Britain placed restrictions on American trade.
France
No. France had already surrendered before the start of the Battle of Britain. Britain was fighting alone apart from some volunteers from several countries.
France
New France
Britain and France on 3rd September 1939 and Poland 2 days before on 1st September
They waited before invading France
Poland.
Great Britain and France.
Britain and France
allies
Congress wanted France to declare war on Britain. France wanted help, and america needed it. Before they did help America, they made America prove they could win.
Appeasement