unnecessary commas

Saw this over at Instapundit:

But perhaps the one trait O’Rourke and Abrams have most in common, is how they are more interested in running for higher office [than in serving] their own communities. Their respective campaigns both failed, and as a rule of thumb, the two should try to win a state-wide election, before running in a national election.

Two of the four commas in the above blockquote are unnecessary. Which ones are unnecessary... and why?

It's time to get back to writing about commas. A quick review of what's already been written:*

Commas, Part 1
Commas, Part 2
Comma Usage: An Aside

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*I've actually blogged a lot about commas, but these are only the most recent posts.