With a substantive address that was among the least partisan State of the Union messages in recent memory, President Donald Trump appears to have impressed a significant majority of Tuesday night’s sizable television audience. Meanwhile Speaker of the House Nancy Pelosi offered a generally respectful welcome to America’s 45th President.

The photograph accompanying this column seems to capture the ambivalence of a Speaker who felt compelled by respect for his office and hers—or by the demands of politics—to welcome Mr. Trump...