(AP) — Congressional Democrats face a daunting assignment. They’re trying to complete a $3.5 trillion, 10-year bill strengthening social and environment programs and raising taxes on the rich. That means they need to rewrite tax, health and environment policy. They might have to reduce the cost dramatically to satisfy moderates. And they must make sure that no more than three Democrats in all of Congress votes against it. If they fail, President Joe Biden’s own party will have dealt him an embarrassing, wounding defeat on the cornerstone of his domestic agenda. Here’s a guide to pivotal differences they must resolve.