(CNN) President Donald Trump's path to reelection was always going to hinge on his performance in a handful of swing states. That path looks more perilous for the President in a series of recent high-quality polls .

But polling over the past month indicates his standing in those battleground states could be fading, bringing those numbers more in line with his national polling.

Here's a look at recent polls from Florida, Michigan, Pennsylvania and Wisconsin, all states Trump won by about a point or less in 2016:

Presumptive Democratic nominee Joe Biden led Trump by six points in a University of North Florida poll and four points in a Quinnipiac University poll . The previous polling average of probability polls had Biden up 2 points.

Michigan: Biden was up by eight points in a Biden was up by eight points in a Fox News poll compared to the prior polling average of probability polls that had him up five points.

Pennsylvania: Biden held an eight-point advantage in a Biden held an eight-point advantage in a Fox News poll , while he was up just three points in the longer term probability polling average.

Wisconsin: Biden was ahead by three points in a Biden was ahead by three points in a Marquette University Law School poll . The longer term probability polling average had the race tied.

Now, we're just looking at four polls here, so I don't want to make too much of it. It is interesting, however, that Biden seems to be doing better than his longer term averages in this limited state polling data, while he is not doing the same in the national polling.

Biden's lead nationally in those polls has been consistently around six to or seven points, as it is now in those.

Could it be that Biden is eliminating Trump's relative advantage in the swing states compared to his national standing?

Take a look at recent national polls from ABC News/Washington Post, CNN/SSRS and two from Monmouth University. Thanks to the Roper Center archives we can drill down to the state level in these polls. Specifically, we can look at the 15 closest states in the 2016 election.

Over the last month, Biden was up by about two points more in these 15 states than he was nationally in these same polls. That's quite different from 2016 when Hillary Clinton did more than 3 points worse in these battlegrounds than nationally.

Now, I do want to be cautious on this. This aggregate data is not a substitute for state polling, but this latest data supports the individual state polling trend.

CNN/SSRS polled these 15 states in December January and early March . Every single time, Trump did better in them than he did nationally, regardless of how the data was weighted. Trump did about 5 points better on average in these 15 states than nationally. We're looking at 1,200 interviews in the four national polls taken in about the last month and a slightly higher number in the three previous CNN/SSRS polls, so the trend seems noteworthy.

What would cause Trump to lose his relative advantage in the battleground states compared to the nation as a whole? It's not clear. One thing that may be happening is Trump seems to be doing somewhat better among younger voters and considerably worse among older voters than he did in 2016 . A number of the larger swing states tend to have large senior citizen populations

Look at the three polls that were released just on Wednesday, and you see it well. Biden led by 10 points among those age 65 and older in Florida,18 points among baby boomers in Michigan and seven points among baby boomers in Pennsylvania.

The timing of the shift does seem to line up with the coronavirus pandemic. It could be that voters are critical of Trump's handling of it. Although Trump's approval rating for handling the virus is not awful, it is consistently lower than the ratings other public officials have gotten in these states. Michigan Democratic Gov. Gretchen Whitmer's approval rating was 19 points higher on the issue than Trump's, for example.

It's also wise not to look past the fact that Biden is well-liked among seniors. He had a higher favorable rating among baby boomers (or those age 65 or order) in all three state polls released on Wednesday. If this shift in the swing states is indeed real and holds up, it could mean a dramatic altering of Trump's chances. Outside of a brief moment after the 2016 Republican National Convention, Trump has never once led his major party opponent (Clinton in 2016 and Biden in 2020) nationally. Most smart analysis that gives Trump a real chance of winning is at least partially counting on him doing better in the swing states than nationally.

Were, in fact, Biden be the one who outperforms in the swing states, then Trump's chances slim significantly. Even if there is no difference between the swing states and what happens nationally, it would lessen Trump's chances.

Trump better hope this new data is more a blip than anything long-lasting.