[wideawake]

However, depriving the North's ability to fight (i.e. sacking their means of making artillery pieces by destroying 90% of their artillery making ability in Pittsburgh) would have been fruitful towards that goal.

That would have caused a temporary supply interruption.

Destroying Meade's army and threatening Washington might - might - have given the UK government political cover to intervene in the Union blockade.

Ultimately I think this would have failed as well, because the US government would probably have just relocated to New York or Boston and have won over UK public opinion to the point where the UK would not have risked further escalation.

[Old Teufel Hunden]

"That would have caused a temporary supply interruption."

Not, it would have caused a major supply interruption. It would have dragged the war on for years IMO. As for England, the political leaders would have loved for the south to win. It would have been good for Britian. For one thing, their textile industry depended on the South's cotton. For another thing, breaking up the fledgling America would have eliminated a potential rival on the world stage. However, England was very anti-slavery and public opinion would have never supported England's direct involvement in the war on the South's side.