Just how badly did Joe Biden damage his and Democrats' prospects with the presidential debate that he himself demanded? The first reliable polling on that question has begun to emerge, and the answer seem to be ... massively. 

According to a new CBS News/YouGov poll of battleground states, voters have shifted to Donald Trump in large enough numbers to change the trajectory of the race. But that's not the worst part for Democrats:

The race for president has shifted in Donald Trump's direction following the first 2024 presidential debate.  Trump now has a 3-point edge over President Biden across the battleground states collectively, and a 2-point edge nationally.

A big factor here is motivation, not just persuasion: Democrats are not as likely as Republicans to say they will "definitely" vote now.

The lead edges up to four points when considering all of the candidates on the ballot, 44/40. That's because Biden voters are looking for a way out, and that gets worse for Democrats the more CBS/YouGov drills down into the data:

Meanwhile, half of Mr. Biden's 2020 voters don't think he should be running this year — and when they don't think so, they are less likely to say they'll turn out in 2024, and also more likely to pick someone else, either Trump or a third-party candidate.

GOP voter enthusiasm has hit 90%, an amazing number that has implications for races all the way down the ballot. Democrat enthusiasm is relatively high still, at 81%, but trailing significantly behind Republicans. That may well reflect determination to vote for other offices too.

What about Biden's age? CBS/YouGov asked about that too, and found that the debate-night assessment has set into place despite the roaring pushback from the White House and Team Biden. Nor did Biden's lame attempt at a "convicted felon" attack change any minds:

Immediately following the debate, CBS News' polling showed increasing numbers of voters believing Mr. Biden did not have the cognitive health for the job and that he should not be running. A large seven in 10 still say he should not be running. (It's three points fewer now than immediately after the debate, perhaps because the Biden campaign pushed back on the idea, but remains the dominant view among voters, and of a sizable four-in-10 share of Democrats.)

Mr. Biden did not gain any ground on Trump on a number of personal qualities: Trump leads Mr. Biden on being seen as competent, tough, and focused. The president continues to be seen as more compassionate.

It's not just CBS/YouGov tracking cognitive health as an issue before and after the debate. CNN polled on the topic immediately after the debate too, and found similar numbers of voters believing that Biden has no business running for a second term. CNN pollster Harry Enten also dispensed with the "Reagan had a bad first debate too" pushback when discussing the poll results with Anderson Cooper on Monday night. That's "total bunk," especially when considering the context in 1984:

Re: Biden's age/mental acuity in the voters' minds. The numbers are worse than pre-debate, which were historically bad. Far worse than 2020 when age actually wasn't a big issue to voters.

The comparison to Reagan is total bunk.

Unsure how Biden wins if #s don't vastly improve pic.twitter.com/46nP2gPEYf

— (((Harry Enten))) (@ForecasterEnten) July 2, 2024

COOPER: There is some comparison being made between Biden's first debate performance and Ronald Reagan's. And there were questions raised after Reagan's first debate performance. He came back with a second better one.

ENTEN: He came back with a second better one. But the fact is, if you look at the numbers that Ronald Reagan had after that first debate, the percentage of voters who said that Ronald Reagan was too old, look at this, it was just 27 percent. It was 27 percent.

Age was an issue at 27 percent. Now --

COOPER: That was after the first debate.

ENTEN: That was after the first debate. That wasn't before the first debate, that was after the first debate. And I averaged two polls there. So it's not like we're just looking at one number back in '84. We're looking at two polls averaging together. There's 27 percent who said that Ronald Reagan was too old.

Now, that number for Joe Biden, who says that he doesn't have the mental fitness to be president, is well more than double. It's 72 percent. Ronald Reagan was able to recover in that second debate because voters were willing to give him the benefit of the doubt. The fact is, voters might have been willing to give Joe Biden the benefit of the doubt going to the first debate. But afterwards, I don't see it.

It's actually triple the level of those questioning Reagan's fitness after the first debate. It's almost 3 in 4 voters who think Biden's too old for the job. In comparison, 49% say that about Donald Trump -- still high, but not nearly as much. And that's because while Trump would be 78 at the start of his next term if he wins, he doesn't exhibit any physical or mental signs of cognitive decline. Biden sends out constant signals of decline in all contexta, even while the media covers for him with propaganda about "cheap fakes," dictated by the White House to the stenographers in the briefing room and in cable-news networks.

By the way, we now have more than a half-dozen national polls out taken after the June 27 debate. Trump leads in all except a Reuters/Ipsos poll where he ties with Biden. On June 27, Trump led Biden in the RCP aggregate average 46.6.45.1, but the gap is now 46.5/44.1.

Democrats had better worry what that means in House and Senate races. And in fact, they already are.

Former Rep. Tim Ryan (D-OH) says if President Biden doesn't step down from the Democratic nomination, "it will be brutal" for down-ballot Democrats. Ryan tells @chueyburns that incumbent Democrats seeking reelection, like Sens. Brown, Tester and Casey, will be hung "out to dry." pic.twitter.com/q0Hdeg8OMj

— CBS News (@CBSNews) July 2, 2024