After years of saying he can't do anything about the border, President Joe Biden suddenly realized he can. And, he's going to.

News dropped earlier today that the Biden administration is preparing executive action to curb illegal crossings at the border - though the details are not quite clear as differing reports suggest different policies. Overall, however, Biden's move seems to clearly be a political response to a campaign issue.

READ MORE: Biden Expected to Sign Executive Order to Seal the Border and Restrict Asylum

However, the Biden administration's weakness on the border has several of his Senate allies worried, and while the White House has invited Democratic Senators to join Biden for an event where he'll announce his new executive actions, we're now getting reports that some of those colleagues - the ones in swing states - might be planning to skip.

Several Democrats in competitive Senate races declined President Biden's invitation to join him Tuesday at the White House when he announces drastic new action, meant to crack down on illegal border crossings, Axios has learned.

Why it matters: Lawmakers in swing states have pushed for stricter border rules, but some may keep the president at arms length as they consistently poll better than him in their states.

• The White House invited all Democratic senators to join Biden at an event announcing the new executive actions. But at least Sens. Jon Tester (D-Mont.), Tammy Baldwin (D-Wisc.), Jacky Rosen (D-Nevada) and Bob Casey (D-Penn.) — all of whom are seeking re-election in battleground states — will not attend.

Some of those Senators cited scheduling conflicts, but the overall message seems to be clear: You're hurting us.

The Biden plan will mirror the rejected "bipartisan deal" from earlier this year, a deal that ended up being flatly rejected by Republicans because it does not close the border. Instead, the action will restrict border crossings after asylum claims reach a certain threshold.

That won't fly with Republicans, who claim that there have already been too many crossings and the Biden administration has been flagrantly ignoring immigration law as it stands. 

The fact that vulnerable Democrats in the Senate feel as though their own president is a drag on their poll numbers is a very bad sign for the incumbent president, who himself is up for re-election this year. They are looking out for their own re-elections and don't see how supporting Biden's re-election strategies benefit them, which is an indication that they believe he is toxic.

Of course, there is a chance that this is all really just a series of scheduling conflicts, but all of the above-named Senators are in vulnerable states, and it seems that all of them are polling better in their own states than Biden.

It puts them - and Biden - in a difficult position when they can't be seen with him. Biden, more than any other incumbent in recent memory, desperately needs to show party unity right now. There are a lot of signs his party's members don't have faith in him. They also need to show their voters that they believe in the work Biden is doing, in order to encourage the maximum number of Democrat voters to turn out in November.

But if they are looking at the data and determining they can do it without (if not outright in spite of) Biden, then he must be extremely vulnerable in those states.