regardless of what someone does or does not so

[epistolario]

I came across this sentence online:

But Pelosi sounded defiant, telling the AP that Trump was “impeached forever” regardless of what the Senate does or does not so. (New York Post)​

What is the purpose of the last word so in that sentence?

Please confirm if these modifications are also possible without changing the meaning of the original sentence:

a) ... regardless of what the Senate does or does not.​

b) ... regardless of what the Senate does.​

 

[Florentia52]

Are you sure you copied it correctly? It should be "...does or does not do"

 

[epistolario]

Are you sure you copied it correctly? It should be "...does or does not do"

Yes, I did. There is a link to it. So it's just a typo?