True Blue is Madge’s song from 1986 and it made #3 on Billboard’s Hot 100. Apparently it is about how pure her love with Sean Penn was – at the time! But the term “True Blue” has political meaning beyond the dance pop ditty’s scope:
In Canada, the Conservative Party has had a wing or faction known as Blue Tories. These true blue adherents support less government involvement in the economy.
True Blue in Canada can also refer to the French term, pure laine, or pure wool (or dyed in the wool). This all roughly means one has direct ancestry to the original settlers of New France. In other words, true blue as in authentically, originally French-Canadian. The term is sometimes used pejoratively here, too, to impugn those lacking such historic blood lines.