Pittsburgh, lighten up! It's a metaphor. It could have been Palookaville, for all anyone cared. The point is the alliterative value, not the place. I'm sure the writers understood this, but given the opportunity to bash the president was too appealing. The "soot choked" city that no longer exists is the result of sound environmental policies brought on by the city and state, not some far-flung, non-binding, trillion dollar boondoggle. The president favors good environmental policies, not empty promises that are uniformly unfair to the US, whether it's trade or climate. Regarding the Paris accord, it has been pointed out that, regarding the Paris agreement, "Obama did an end-run around the two-thirds Senate vote required to ratify any treaty . . . .", instead choosing to legislate by executive order. Why? Because Obama understood the vote would fail in the Senate.