Recent reports have Donald Trump and his family splitting their time between Washington and New York, with him mostly in Washington and them mostly in New York. His children, who were his main business partners and confidants, have a restricted interaction with him due to conflict of interest concerns.

Like most salesmen, Trump revels in the conquest, not the execution. He achieved his goal of vanquishing his Republican rivals in the primaries and Hillary Clinton in the general election. But now he has has settled into the more mundane task of governing, conquering legalese and minutia.

Sure he will be thrilled to get some of his main campaign promises passed. But even that will be a slog, assuming he can get them through congress. Opponents will challenge him in court. States will throw up roadblocks. His glass will be half full, not overflowing.

When he solicited John Kasich to be vice president, Trump made it clear that he was only interested in the celebrity half of the presidency and not very keen on the day to day responsibilities. Has anything really changed? How long until being cut off from his family and playing a part that does not fit his nature wears him down?

Will he delegate everything to Mike Pence, his vice president? Or will he find an excuse to walk away when it isn’t any fun anymore and he has nothing left to prove, like after helping the Republicans stay in power in the 2018 midterm elections?

A half life in physics is the time required for something to fall to half its value.The half life of Trumps presidential aspirations could be sooner than anyone expects.