(CNN) Donald Trump won the 2016 election for one very simple reason: People wanted radical change and he was the candidate who offered that change.

Trump's greatest strength as a candidate -- and as President -- was the belief that he was going to shake things up. That he was a change agent, a heat-seeking missile aimed directly at the status quo.

Which is why new numbers from a national CNN poll have to be very concerning for Trump. Yes, his overall job approval rating is down to 36%, a 6-point drop since last month and the lowest he's been since February. That's concerning not just for Trump but for Republicans on the ballot this fall who are hoping Trump's approval numbers will be inching upward rather than downward with eight weeks left before November 6.

The roots of that rising disapproval may well be in the "change agent" question. Check out Trump's fade on the issue via CNN polling on the question of

November 17-20, 2016: 49% applies to Trump/49% does not apply to Trump

April 22-25, 2017: 48%/51%

August 3-6, 2017: 43%/55%

November 2-5, 2017: 40%/56%

March 22-25, 2018: 45%/52%

September 6-9, 2018: 40%/57%

That's not a trend line that will bring a lot of smiles to the White House. Of course, it's also a somewhat predictable decline given that Trump essentially promised to destroy Washington as we know it before coming into office. Making that sort of pledge works in the setting of a campaign -- especially when people are mad as hell at both parties and are in a mood to do the opposite of what Washington has been doing for decades.

The problem with campaigning as the change candidate is that you then have to be president. And making good on all the change you promised is virtually impossible -- because a) the bureaucracy is a very big thing to tackle and b) "change" doesn't mean the same thing to any two people who voted for Trump because of it.