From an article in Foreign Policy:
The Soviet Union is no more, but the entity created specifically to
counter its military might thrives, as has the Pentagon's budget,
which increased relentlessly until 2011, topping $700 billion.
I wonder if the use of 'as has' here is grammatical. Shouldn't it be 'as does', that is, 'as the Pentagon's budget does thrive':
The Soviet Union is no more, but the entity created specifically to
counter its military might thrives, as does the Pentagon's budget,
which increased relentlessly until 2011, topping $700 billion.
After all, the verb phrase used for comparison contains the verb 'thrives', not 'has been thriving'.
Best Answer
These are two sentences combined into one:
This is talking about the present. Said "entity created specifically to counter its military might" is still thriving at that point.
This talks about the past. The Pentagon's budget increased before this point. It does not, however, tell us if the Pentagon's budget is still thriving, so we can't use the present form "does" here. We could use "did":
The "As" here simply refers back to "thrives" and indicates, as above, that "the Pentagon's budget" thrived just like "the entity created …".
The choice between "has" and "did" here is mostly at the author's discretion. Personally, I would pick "has" instead of "did" because "did" implies the budget increased completely on its own, but as I said, both would be grammatically correct.