Pompey had been almost miraculously fortunate up to this period of his life's career.

He had done infinitely valuable service to the State.

He had already crushed the pirates.

There was good ground for believing that in his hands the Roman arms would be more efficacious against Mithridates than in those of any other General.

All that Cicero says on this head, whatever might have been his motive for saying it, was at any rate true.
A man desirous of rising in the service of his country of course adheres to his party.