I have long argued that the only real meaning of any U.S. election is that the winner got more people to vote than the loser. [Of course, this year's presidential election requires an asterisk: more people to vote in each of the states for their electoral college votes.] In most cases, the post-election punditry is meaningless. The few special cases are those wave elections like 1994, 2006, and 2010, which didn't include presidential contests and 1952 and 1980 which did.
It's especially misleading to draw Big Conclusions from the mixed results of 2016. The loser got significantly more votes than the winner. There were few changes in Congress, all in favor of the loser's party. Voting was lower than in recent presidential years. Kevin Drum cites more arguments along with refutations. My point is that you can't really say that there was a surge of angry white voters, just that enough of them turned out in Rust Belt states to turn them red compared with recent years. Nor can you say that the Trump administration has any special mandate. If anything the election just showed that the public was unenthusiastic about both candidates and that the highly negative campaigns led many voters to stay home.
With the votes so close in the surprising swing states [Wisconsin, Michigan, and Pennsylvania] any of several factors could logically, but not determinatively, have made the difference: Russian hacking, Comey letter, numbers of candidate visits, etc. Since we can't be sure of the causes, we should be very careful about asserting consequences and "lessons."