From the article,"An overwhelming majority of Democrats, 86 per cent, are fans of the deal, while only about 51 per cent of Republicans say the US should take part in the accord, the programme reported."

So, not 70% of his supporters, especially considering not all Republicans voted for him, and some Democrats did.

And the math is funny anyway. I haven't seen recent registration numbers, but last I looked, it was roughly 1/3 Democrat, 1/3 Republican, and 1/3 unaffiliated. It might be 40%, 30%, and 30%, not sure; the point is that I seriously doubt 70% of the people who voted for Trump support the Paris treaty, and certainly this article does not say that, though it tries very hard to imply it.

The gov't of the US should represent its people, not just the side who won.

And the people of the U.S. should support their president, even if they didn't vote for him.

Sorry, I'm not making or am swayed by emotive arguments, and no one should be. Nothing in the constitution or in established interpretation of it require citizens to support the president.

And nothing in the Constitution requires the president to follow popular opinion according to British papers. That's the job of some portion of the members of Congress.