A House Democrat is calling for Congress to review the 25th Amendment of the Constitution, suggesting President Donald Trump is mentally "unstable."

Rep. Earl Blumenauer (D-OR), who has represented a Portland district for 20 years, wrote in an op-ed that the 50-year-old amendment contains a "fatal flaw" that must be addressed.

The 25th Amendment relates to the procedures for removing a president or vice president "in the event of death, removal, resignation, or incapacitation."

Blumenauer cautioned that the amendment - ratified after the JFK assassination - would "fail" in the case of a president who is "mentally unstable, paranoid or delusional."

He wrote: 

The erratic behavior of Donald Trump has raised new questions about his mental and emotional capacity to discharge the tremendous burdens of the most powerful position in the world. It is the president who has the ability to launch nuclear weapons, unleashing untold devastation on the world. Presidents can create diplomatic chaos or move markets with the most carefully crafted declarations, let alone late-night tweets with the grammar and misspellings of a fifth-grader and decidedly unpresidential tone.

Blumenauer said a bipartisan panel of lawmakers and former presidents should determine if the current president is fit to serve.

Speaking on the House floor Wednesday, Blumenauer argued that Trump has repeatedly made statements that are "demonstrably wrong," including about the crowd size for his inauguration and the weather on that day.

He said he was forming a "working group" to look into the amendment.

Earlier this week, Sen. Al Franken (D-MN) claimed that GOP senators have privately expressed concerns about Trump's mental state. 

"We all have this suspicion that - you know, that he's not - he lies a lot," said Franken.

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