Douglas Harper's Etymology Dictionary
Grand Old Party
see GOP.
Usage examples of "grand old party".
But the Holy Office was shrewd and socially ambitious, and the Grand Old Party was desperately in need of votes, so under the ré.
At the same time, with his secret guidance, you will bring back the Grand Old Party as the champion of the poor.
Nowadays, it's such a well-known political trademark that most people don't have much awareness of its original meaning, any more than folks once thought 'Grand Old Party' when they heard GOP.