It's possible tax reform efforts could fail, as did the attempt to replace Obama's healthcare law. Or an overhaul of the tax system could take much longer than anticipated. The last major tax changes, in the 1980s, took more than two years to enact. 

 Treasury Secretary Steven Mnuchin is changing his tune on how soon Congress might be able to pass a tax reform package. 
 
 In an interview with the Financial Times this week, Mnuchin said that his original prediction that lawmakers would get tax reform to President Trump’s desk by August was “highly aggressive to not realistic at this point.” 
 
 “It started as [an] aggressive timeline,” he told FT. “It is fair to say it is probably delayed a bit because of the healthcare.” 
 
 Mnuchin still expressed confidence that Congress would be able to overhaul the tax system this year. In February, he had predicted that lawmakers would pass tax reform before they leave on their annual summer recess in August. 
 
 His February comments came in an interview with The Wall Street Journal, and he conceded at the time, “That’s an ambitious timeline. It could slip to later in the year.” 
 
 Last month Republicans failed to pass legislation to repeal and replace Obamacare because House GOP leaders failed to secure enough votes in the lower chamber to pass the bill. Afterward, Republicans said they were eyeing tax reform as the next major item on their agenda and planning to use the budget reconciliation process to push it through the House and Senate. The obscure budget procedure allows the Senate to pass certain legislation with a simple majority and not a supermajority of 60 senators.
– It looks like the US won't have a reformed tax system by Labor Day after all. Steven Mnuchin tells the Financial Times that having a tax reform bill ready for President Trump's signature by August is "not realistic at this point." Two months ago, the Treasury secretary said the administration hoped to have tax reform done by the time Congress goes on recess in August, CBS News reports. The Los Angeles Times notes it's a known fact that lawmakers get more done when they have a vacation coming up. But Mnuchin says the failure to repeal and replace the Affordable Care Act pretty much blew up that timetable. While Mnuchin says he still expects tax reform to happen sometime in 2017, there's no guarantee that's realistic either. The last major tax reform effort—back in the 1980s—took more than two years. The setback means US companies will have a harder time planning their budgets, as it's uncertain they'll get that Trump-promised lower tax rate. Trump's tax reform plan calls for lowering taxes for both businesses and individuals. Mnuchin, a former Goldman Sachs banker, says that won't increase the US deficit because the money lost from lower taxes will be offset by economic growth.