Why did emperors eventually stop proposing legislation through the Roman Senate?

In the early Roman Empire, the Senate initially served as a mouthpiece for the emperor, with its decrees acting as a formal mechanism for imperial legislation. However, as the emperor’s position evolved into an absolute monarchy, the Senate’s role became increasingly ceremonial.123

Emperors eventually stopped proposing legislation through the Senate because the body’s approval of imperial proposals became entirely automatic, rendering the process a mere formality. As the emperor’s own legislative power—expressed through edicts, judgments, mandates, and rescripts known as constitutiones principum—became the primary and most efficient instrument of governance, the need to seek senatorial endorsement vanished. By the middle of the 2nd century CE, the emperor had effectively become the sole creator of law, leading to the abandonment of the practice of legislating through the Senate shortly after the early imperial period.21