I'm not a specialist in this subject, so bear with me. I've always wondered why one claims that the electromagnetic and weak interactions are unified, but the strong one with the (unified) other two is not. Mathematically, I'm aware that the full gauge group of the SM is ## U(1) \times SU(2) \times SU(3) ##, so one perceives all three interactions separately and on equal footing. In what exact sense are the weak and the em unified, but the strong not? Thank you!