Trump's speech set a tone for selling his agenda more broadly
This speech was still very Trump, focusing around the theme of putting American interests ahead of global ones. It had the same usual deviations from Republican orthodoxy - calling for paid family leave and a big infrastructure package while ignoring entitlement programs, criticizing free trade agreements and taking a harder line on immigration than most establishment Republicans want.
But it placed those themes in terms that seemed somewhat less aimed at inflaming his base and somewhat more aimed at convincing people that his policies are good for a majority: that tighter immigration will raise wages for all sorts of workers, or that crime-fighting policies will make life better in cities like Baltimore, where he received few votes.
This is a smart political shift, and I honestly thought Senate Minority Leader Chuck Schumer looked rattled discussing the speech on television, as though he had expected the speech to be less strategically competent.
Still, there are at least three significant challenges facing Trump.
One is whether he can implement the policies he's promising.
Trump's failure to staff up his administration hinders both his ability to influence Congress and his ability to change policy through executive action.
The ideas Trump floated on healthcare and taxes are vague. In theory, Congress is supposed to move major legislation on both issues this year. But as Matt Yglesias notes, Trump gave no guidance to resolve the big disagreements on these issues that exist among Republicans in Congress.
As Schumer said, Trump talks about the need to spend big on infrastructure but has not advanced any formal proposal. Axios reported last week that he may not even introduce one until 2018.
A second issue is whether his policies will provide the improvements he has promised, even assuming he gets them enacted.
Trump promised to "expand choice, increase access, lower costs, and at the same time, provide better healthcare." A major reason Republicans can't come to terms on a healthcare reform package is the impossibility of doing all these things at once while lowering government expenditure.
Trump has promised good jobs and higher wages, but the immigration crackdown Trump expects to drive wages up could also cause the economy to shrink and raise consumer prices, as could new trade restrictions.
The determinants of crime rates are elusive - nobody knows exactly why crime fell so much starting in the early 1990s, or why it rebounded recently in some major cities but not others. Plus, the federal role in crime fighting is limited. Whether these trends improve or worsen is largely out of Trump's hands - and if his policies worsen the relationship between police and minority communities, a decline in cooperation could make crime worse.
The third issue is whether Trump can even maintain the level of discipline he showed in Tuesday's speech.
Teleprompter Trump has always been more normal than Twitter Trump. And Teleprompter Trump seemed more refined than ever on Tuesday, mostly able to read prepared remarks without looking bored, except in the last 10 minutes. But Trump will have to go off script over and over again, sometimes in the face of adverse events that will make him unhappy.
During the campaign, best-behavior Trump was typically only able to stick around for a couple of weeks at most. That clock has started again today.