距離上一次美國對稅法進行改革已經過去了30年，現在，美國稅法已經陷入了令人難堪的混亂。如今，唐納德·特朗普即將就任，并且他還面對友好的國會，因此，各界的商業利益團隊越來越相信，他們多年來推動的改革最終將成為現實。但改革的過程不會很輕松。雖然共和黨控制了賓夕法尼亞大道兩端的參議兩院，但現在相對于確定稅法改革的方向，還有更多問題需要找到答案：下面是一些已知的未知因素。

1. 民主黨是否會參與？

共和黨可以通過一種預算規則“調和規則”，完全避開民主黨，使改革方案以簡單多數票在參議院獲得通過。但這種做法也會限制改革的范圍和持久性。另一方面，如果共和黨想要通過常規順序通過一項議案，必須獲得大約八位民主黨人的支持，而他們可能為自己的配合提出苛刻的條件。并且共和黨領導人已經暗示，他們計劃采用迂回戰術，避開少數派。

2. 能夠多快付諸實施？

歷史證明，總統在上任后的半年內效率最高。如果到明年秋天，白宮依舊無法達成一份和解方案，眾議院的共和黨人將把注意力從棘手的政策制定問題，轉移到自己的改選，推動改革的動力將逐步消失。

3. 跨國公司的海外利潤會面臨怎樣的后果？

特朗普曾提議按10%的稅率，對公司在海外隱瞞的約2.5萬億美元利潤征稅，該筆稅收或將用于支持基礎設施項目。而國會的共和黨人似乎更傾向于，把這筆資金用于抵消更低的總體公司稅率。雙方都希望執行按來源地征稅的制度，但對于具體方法卻存在分歧。（財富中文網）

作者：Tory Newmyer

譯者：劉進龍/汪皓

The U.S. tax code has grown into an ungainly mess in the thirty years since Washington last streamlined it. Now, as Donald Trump prepares to take office facing a friendly Congress, business interests of all stripes are gaining confidence that the overhaul they’ve spent years pushing will finally become a reality. But it won’t be easy. Despite Republican control at both ends of Pennsylvania Avenue, there are for now more questions than answers about the direction a tax code rewrite will take. Here, the known unknowns.

1. Do Democrats get to weigh in?

Republicans can freeze Democrats out of the process entirely by employing a budget rule known as “reconciliation,” which would allow a reform package to clear the Senate with a simple majority. But that gambit could also restrict the overhaul’s scope and permanence. On the other hand, the eight or so Democrats whom Republicans would need to pass a bill through regular order could drive a hard bargain for their cooperation, and Republican leaders are signaling they intended to end-run the minority.

2. How fast can it move?

History suggests presidents are at their most productive in their first half-year in office. If the White House isn’t able to forge a compromise by the time the calendar tips into the fall, House Republicans will turn their focus from tough policymaking to their own reelections, and momentum for an overhaul could fade.

3. What happens to multinationals’ overseas profits?

Trump has proposed taxing the roughly $2.5 trillion that corporations have stashed overseas at 10%, potentially to help fund an infrastructure program. Congressional Republicans appear keener to dedicate those funds toward offsetting lower corporate tax rates overall. Both sides are eager to move to a territorial system but propose different ways of getting there.