Roosevelt may have been making campaign speeches saying one thing, but he was clearly planning another. He knew war was inevitable and necessary, and authorized US Naval escorts for British convoys well before our entry into the war, several were torpedoed and at least one sunk before the start of hostilities. Roosevelt was itching to go after Hitler, and Pearl Harbor finally gave him the excuse, and declaration of war, he needed. He was also engaging in a massive naval construction program (he knew the Army could wait, the Brits already had one) so that even right after Pearl Harbor the US already had enough hulls under construction to ensure naval superiority in the Pacific.

But it was lend-lease that kept England, and later, Russia in the war. He knew all along that he would have to fight the Nazis, even though there were strong isolationist feelings in the US.

You can accuse him of lying to the American people to get elected, and manipulating Congress into an unpopular war, but you can't accuse him of being soft on fascism.

"...So Roosevelt needs to find a means to keep supplying the British without antagonizing the isolationists and particularly the Congress of the United States. The idea that he would go through the Congress was unacceptable to him because he knew it would be hung up in some kind of long-winded and painful debate. And this would demoralize the British more than help them. So he invents this thing called Lend-Lease. And he's marvelous at selling it again to the public."

http://www.pbs.org/wgbh/amex/presidents/32_f_roosevelt/filmmore/ra_lendlease.html