WASHINGTON — Rep. Raja Krishnamoorthi, D-Ill., on Monday became the latest House member to support a Trump impeachment inquiry, which for all practical purposes is already being pursued by the House Judiciary Committee.

Of the 13 Illinois Democrats who are in the House, only three— Reps. Dan Lipinski, Bill Foster and Cheri Bustos, who, as chair of the Democratic Congressional Campaign Committee, is part of leadership — have not said they back an impeachment inquiry.

Let me use this column to break down what is happening because there seems to be some confusion out there. Going ahead with an impeachment inquiry and impeachment have been conflated. They are not the same.

A fact-finding impeachment inquiry by the House Judiciary Committee is a needed step that takes place before the panel decides whether there is enough information to go forward with articles of impeachment.

The House Judiciary Committee has subpoena power and does not need any vote from all the House members on whether to proceed with an inquiry.

On Monday, the panel subpoenaed former White House staff secretary Rob Porter, a key figure in former special counsel Robert Mueller’s report, ordering him to testify on Sept. 17.

President Donald Trump, the report said, directed Porter to tell now-former White House Counsel Don McGahn to create a false record suggesting that Trump never ordered McGahn to fire Mueller.

The committee on Aug. 15 also issued subpoenas for Corey Lewandowski and Rick Dearborn, who were part of Trump’s 2016 campaign, to testify Sept. 17.

House Judiciary Committee Chairman Jerrold Nadler, D-N.Y., said in a Monday statement, “The Committee intends to hold hearings and obtain testimony over the coming months as part of its efforts to hold the President accountable as we move forward with our investigation into obstruction, corruption and abuse of power by Trump and his associates. This will help the Committee determine whether to recommend articles of impeachment against the President or other Article 1 remedies. No one is above the law.”

Nadler turned up the heat in June, when he announced more steps the panel was taking to investigate Trump.

On Aug. 22, Nadler asked the chairs of four other committees probing Trump to share information that could be helpful to the Judiciary Committee’s impeachment investigation.

Krishnamoorthi sits on two of those committees, the Committee On Oversight And Reform and the House Permanent Select Committee on Intelligence.

In a statement Krishnamoorthi, who represents the northwest suburban 8th District, said, “We have now come to a point where we must engage in an investigation to not only expose wrongdoing and prevent it from happening again, but also to determine whether the current President engaged in behavior meriting the beginning of impeachment proceedings.”

“Where this investigation leads, we cannot know at this time. Regardless of the outcome, I support Chairman Nadler’s impeachment investigation conducted in accordance with the Constitution.”

I asked Krishnamoorthi when we talked Monday afternoon about what’s going to change now that more House members — almost only Democrats — are coming out for an impeachment inquiry.

Said Krishnamoorthi, “I think it’s fair to say that (Nadler) feels that he has the tools necessary to conduct the equivalent … of this impeachment investigation. But he’s also trying to gather information from the other committees. Since I’m part of two of the committees that is playing a pretty heavy role in investigating wrongdoing by the administration, I wanted to put my foot in the camp of those who would cooperate with (Nadler’s) investigative activities.”

Editor’s note: This story has been corrected to add Rep. Bill Foster, D-Ill., to the list of Illinois House Democrats who have not called for an impeachment inquiry.