This is how well President Trump's first few weeks in the Oval Office have gone, according to the American people:

That's Gallup's daily tracking poll. And as steady polling declines go, it's about as steady as they come.

Trump's 55 percent disapproval rating is already as high as President Obama's ever was in his first term in office. And it took other presidents hundreds of days before a majority of the country decided they weren't impressed.

Infographic: Trump Reaches Majority Disapproval In Record Time  | Statista

But this is not unfamiliar territory for Trump. He's now president, yes, but his image rating — previously tested as favorable vs. unfavorable rather than approve vs. disapprove — was regularly below 40 percent as a candidate. He won the Republican nomination despite it, and then he won the presidency despite it.

So, if anything, this seems to be a little bit of the honeymoon (such as it existed) wearing off. Americans were split on Trump upon his inauguration on Jan. 20; now they've reverted to majority concern. Fifty-four percent of the people didn't vote for Trump, and now 55 percent disapprove of him.

But when will we know Trump's really in trouble? When do we start talking about his base crumbling and his own supporters starting to head for the hills?

We're still a ways off that. The Republican Party eventually rallied to Trump after he won its nomination, as parties tend to do, but it took a while. (The same happened with Hillary Clinton and Bernie Sanders supporters, eventually.)

Both Gallup and Washington Post/ABC News polling between the July Republican National Convention on the November election showed Trump's favorable rating between 30 percent and 35 percent, with his unfavorable rating as high as the low 60s. Even on the eve of the election, Gallup had Trump at 34 percent favorable and 62 percent unfavorable. Days later, he won the presidency.

Here's how it looked over the course of his campaign, using the RealClearPolitics average. His average favorable rating crested 40 percent only after he was elected:

So it's hard to say that Trump's really in trouble right now, relatively speaking.

And a big reason is that the only party he really needs to appeal to — his own — is still onboard, as it has been for a while. Even in June, at the bottom of Candidate Trump's image ratings — 29 percent favorable vs. 70 percent unfavorable — he still had the support of 65 percent of Republicans. About 34 percent of Republicans had an unfavorable view of their soon-to-be nominee.

Even in such a case, though, Trump could arguably still govern. Republicans, after all, have majorities in both chambers of Congress, and the vast majority of Republicans in Congress come from safe districts and states. As long as a majority of their primary electorates liked Trump, these members would feel pressure to support him.

For comparison's sake, even at his worst, only 4 in 10 Republicans disapproved of George W. Bush. That was in October 2008, as the financial crisis hit and Democrats were preparing to win the presidency back.

We have seen rock-bottom for Trump, though; it just happened to come before he launched his campaign. Back then, just 16 percent of Americans had a favorable impression, while 71 percent had an unfavorable one. This was when Trump didn't have a base and when even Republicans were anti-Trump. Nearly two-thirds of them — 65 percent — had an unfavorable view of Trump, and just 23 percent had a favorable one. (Hence, all those stories about why he couldn't win.)

By July 2015, a few weeks after Trump's campaign launch, his overall favorable rating doubled to 33 percent. And it stood between 30 percent and 40 percent throughout his campaign.

If he winds up in that same range as president, it may be difficult to govern and get Republicans to go along with his every wish. But the GOP majorities he enjoys will make it possible.

Should he drop further, that's when he'll be in real trouble; that's when the American people — and, specifically, Republicans — will have decided that he really is just the big-talking reality TV star they thought he was back before he ran for president.