House Speaker Nancy Pelosi is being politically smart by holding off on a formal Trump impeachment vote on the chamber floor, according to Brit Hume.

However, the investigation she is engineering is "peculiar" and unlike past proceedings against ex-presidents like Richard Nixon, Hume claimed Tuesday on "Tucker Carlson Tonight."

"I frankly can't think of a good reason, from her point of view, why she would hold a vote," he said.

A full vote, the Fox News senior political analyst said, would expose vulnerable Democratic lawmakers -- especially those in districts won by President Trump in 2016 -- to a vote that could hurt them politically.

PELOSI ANNOUNCES HOUSE WON'T VOTE NOW ON WHETHER TO BEGIN IMPEACHMENT INQUIRY

"This way, she gets to get all the fruits of this peculiar investigation that she announced going on, and none of the downsides," he said.

"They're conducting a very unusual investigation."

Pivoting to Nixon, Hume said the House engaged in a balanced and fair process during that investigation.

The Republican minority was able to engage in the process and call witnesses, and the proceedings were largely not held behind closed doors, he added. "None of that is happening here."

However, he said while Democrats' investigation has gone on, national polling shows growing support for impeachment, as well as impeachment-and-removal.

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Late Tuesday, Rep. Pelosi, D-Calif., announced after meeting with the House Democratic caucus that there would be no vote -- at least for now -- on the launch of formal impeachment proceedings against Trump.

"There's no requirement that we have a vote, and so at this time we will not be having a vote," Pelosi said.

"We're not here to call bluffs -- we're here to find the truth, to uphold the Constitution of the United States. This is not a game for us. This is deadly serious."

Fox News' Gregg Re contributed to this report.