Midway through former President Donald Trump’s historic second impeachment trial, the social media silence is almost deafening. Mr. Trump, of course, was permanently banished from Twitter on Jan. 8, two days after the Capitol riot he is blamed by Democrats for inciting. The ex-president has also made no TV or radio appearances since leaving office. This pause in Mr. Trump’s relentless public presence could be serving him well. His poll numbers have rebounded a bit since plunging after the Jan. 6 sacking of the Capitol by his supporters. In some ways, the former president is two entities – a man and an idea. Mr. Trump the man has a solid base of diehard supporters, giving him the potential to stage a political comeback and become the first U.S. president to win a nonconsecutive second term since Grover Cleveland in 1892. Mr. Trump the idea represents a breed of political thought – “conservative populism” – that could be the key to success for other Republican politicians going forward.