A majority of Americans say that President Trump’s actions regarding Ukraine are a serious matter and merit an impeachment inquiry by Congress, but a plurality says that, based on what they know now, the president shouldn’t be removed from office, a new Wall Street Journal/NBC News poll finds.

The survey suggests that the public is closely following House Democrats’ investigation but isn’t convinced that Mr. Trump should lose his job over accusations that he misused his office by pressuring Ukraine to investigate a political...