The man who led Malaysia through the final two decades of the 20th century and has waded back into its politics in recent months said Thursday the country’s current government is deeply problematic and “must go.” Mahathir Mohamad, now 92, was Malaysia’s prime minister from 1991 until 2003. Today, he has emerged as an unlikely rallying point for an opposition coalition stocked with people who once despised him. He has recently taken a strong stance against Najib’s government, saying his one-time protégé is corrupt and has elbowed Malaysia backward instead of propelling it forward.