According to the Pennsylvania State Capitol website, the building was intended to be a Palace of Art. Even with such a small example as there is on this postcard, I can well believe it. The dome was inspired by the dome of St Peter's Basilica in the Vatican. This is the third capitol to have been built in Harrisburg, the first having been destroyed by fire and the second left unfinished when funds dried up.
From the back of the card:
Exterior and interior views of the magnificent dome of Pennsylvania's State Capitol Building located on Capitol Hill in Harrisburg. The dome is 272 feet high and weighs 52 million pounds.