Only AFTER 6 million lay dead, at least 750,000 thanks directly to his actions.
Meanwhile, people like Republican Congressman Hamilton Fish of New York (despite the name, not remotely Jewish!), had supported the establishment of a Jewish homeland in the Land of Israel long before WWII broke out. And Fish was no interventionist.
That's a quote taken from the posted New York Slimes book review. Not sure if it's even accurate; I don't recall ever hearing or reading about Roosevelt speaking out on a Jewish homeland in Palestine. (Generally speaking, historical revisionism is not unusual in the writings of the left-leaning journalists of the MSM.)
What did happen is that the Republicans first put a plank in their 1944 platform supporting a Jewish state in Palestine, and the Democrats - sensitive to Jewish voters - followed by doing similarly at their convention a bit later.
Whether or not the sickly Roosevelt, running for a fourth term that year, ever explicitly endorsed that position, I honestly don't know.