For all the four-alarm fires around President Trump this summer — Putin, Mueller and Cohen, oh my! — his approval ratings have barely moved, as you can see from this remarkable chart of SurveyMonkey’s weekly tracking poll.

Be smart: Trump's narrow trading range is both the reason he messages only to his base (no one else is gettable), and the reason he has to keep amping up for the volume for his true believers (he has nowhere else to go).

There are danger signs:

• The high approval for Mueller in Friday's Washington Post-ABC News poll (63% support his investigation) was sobering for Trump strategists.
• Only 18% support a pardon for Paul Manafort, despite Trump's tweeting on behalf of his former campaign chairman: "I feel very badly for Paul Manafort ... Such respect for a brave man!"
• MSNBC analyst Matt Miller said 18% is therefore the base of the base — the "stand in the middle of Fifth Avenue and shoot somebody" number.

A closer look at the SurveyMonkey numbers:

• They’re not good: He hasn’t cracked 50% approval in this poll since the day he took office. But other than a few dips along the way, he has rarely fallen below 40%, even with the recent crises.
• His negatives are stronger than his positives — the people who don’t like him really don’t like him.
• The percentage of people who strongly disapprove of him in the SurveyMonkey polls — generally in the low to mid-40s — is remarkably close to the 44% who said in the most recent Axios-SurveyMonkey poll that they’re ready for Congress to begin impeachment proceedings.

Between the lines: The Post-ABC poll Friday appeared to show movement, with a record 60% disapproval rating for Trump that had jumped four points since April.

• But the numbers look more stable when you compare it to previous Post polls, and nearly all of the movement is within the margin of error, since the Post’s sample size is smaller than SurveyMonkey’s.