The man who promised to make America great is making America very nasty. The greatest challenge for those opposing this President is not to sink to his level of rude and vindictive politics. That is a challenge that has eluded some Americans over the past week.
Donald Trump's Secretary of Homeland Security, Kirstjen Nielson, was hounded from a restaurant by protesters and the White House press secretary, Sarah Huckabee Sanders, was refused service in a restaurant whose owners did not want her there.
These things do not happen in mature democracies. No matter how impassioned political arguments become, protagonists normally recognise each other as people with personal rights that ought to be respected.
Nielson might not be well known outside Washington DC but Huckabee Sanders appears on television conducting White House press briefings just about every day. She serves an impulsive, inconsistent President given to abusive tweeting and absurd assertions of fact. She does her best to put a reasonable face on it all with professionalism and patience.
Both women are doing a job somebody needs to do and do not deserve to be subjected to personal insults in their private lives. To be refused service in a restaurant by owners of the opposing political view is stark evidence of how deeply America has been divided by Trump.
It was divided before, of course, that was how such an unusual candidate came to power. But his behaviour from the moment he took the oath of office has been designed to deepen the wound.
He knows the more he disgusts and antagonises the half of the country who did not vote for him, the more he appeals to the half that did. He has managed to polarise American politics so that he now dominates the Republican Party much more than he did before the 2016 election.
Republicans in Congress are at risk of losing their seat in party primaries if they oppose him and better Republicans, such as House majority leader Paul Ryan, are retiring at the mid term elections in November.
If the Democratic Party is to win control of the House in November and find a candidate who can beat Trump in 2020, it will not be by descending to his level.
House minority leader Nancy Pelosi struck the right note, criticising the restaurant owners' refusal to serve the White House press secretary as "predictable but unacceptable".
Her colleague, Congresswoman Maxine Walters, went the other way, telling a crowd, "If you see anybody from that Cabinet in a restaurant, in a department store, at a gasoline station, you get out and you create a crowd and you push back on them."
That, of course, was up Trump's alley. He called her "an extraordinarily low IQ person" who had "just called for harm to supporters ..." and had "become, together with Nancy Pelosi, the face of the Democrat Party".
That mix of insult, falsehood (implying she called for physical harm) and unfair smear of Pelosi by association, is his style. Americans need to raise their sights to make their politics great again.