The Republican tax plan starts with big advantages, and big problems that make the outcome of the debate uncertain.
Let's start with the advantages.
American business wants it to pass. Corporate executives, who complain the top U.S. rate of 35 percent hobbles them against foreign competitors, get a large cut to 20 percent. Unincorporated "pass-through" businesses get a 25 percent top rate, down from the 39.6 percent they can now face under the individual tax code.
Republicans believe deeply in tax cuts, both as a means of limiting government and as a tool for boosting economic growth. They control both Congress and the White House and operate under rules that allow them to enact their plan without a single vote from Democrats.
Moreover, those Republicans increasingly see tax cuts as a matter of political survival. With their business donors and voting base already dispirited over failures on other issues such as health care, botching tax cuts trigger a collapse that hands Congress back to Democrats in 2018 elections.