President Donald Trump's 2018 budget informally begins the race toward the goal Republicans
The first obstacle is the halting effort to repeal and replace Obamacare. Until it concludes, Republicans can't enact their tax-cut goals.
The second is the difficulty of passing a 2018 budget. Republicans can't pass their tax cuts until they do that, either.
"It's not going to be this year," said Bill Hoagland, a longtime Republican budget aide in Congress, now at the Bipartisan Policy Center. And given the challenges, he predicted, "The only way they can do tax reform at this point is bipartisan."