Let's be real, he was elected for the following reasons:
He ran as a Republican
He ran against Hillary Clinton
He had some sort of platform
The first two are the only ones that really matter, but I included the distant 3rd one for the sake of arguing your statement. So let's go through this line by line.
He is supported by the voters who elected him.
WAS. Or at least "...is supported by SOME..." Latest Gallup puts his job approval rating at 39%. Simple math would indicate that a large portion of those who voted for him are unhappy with his performance so far.
This is why we have elections, to determine who formulates policy. In the opinions of the voters who elected him, his policies benefit the country.
The first sentence is true! If that 3rd reason I listed mattered to some of the voters, then the 2nd statement is also true, but only if you rephrase it to say, "...the policies he promised benefit the country." The distinction is important I think, since so far none of the major policies he promised have been successfully implemented.
That is what elected officials are supposed to do, abide by the wishes of their constituents.
This is also true, and if you can name with a straight face a single politician who has done this in our lifetimes, then I will quietly exit this pointless conversation. Including this statement as part of your argument makes you sound foolish.
Lastly, the rumblings in the news today seem to indicate that the President's tweet about transgenders in the military was at best (as usual) ready-fire-aim, as none of his subordinates in the actual military or defense department have anything resembling marching orders regarding this policy. Is it too much to ask to keep policy decisions off twitter until they are finalized? Speaking of twitter, this guy's tweet history is packed full of gems. A few industrious people with an axe to grind mine and regularly post them here
when he flatly contradicts himself. Amusing.