Sens. Robert Menendez (D-NJ), Dick Durbin (D-IL) and Patrick Leahy (D-VT) reportedly sent a threatening letter to Ukraine last year demanding they help in special counsel Robert Mueller's investigation into potential Russian collusion. They were specifically interested in former campaign manager Paul Manafort's role.

According to Sen. Rand Paul, those three threatened to pair back military aid for Ukraine if the country didn't honor their request.

So, “If you’re going to condemn Trump, you need to condemn the Democrat senators,” Paul told “Meet the Press” host Chuck Todd on Sunday.

Rand Paul: “Four senators, Democrats, wrote a letter to the Ukrainian government and said, ‘If you don't keep investigating Trump we may reconsider our bipartisan support for your aid ... Someone needs to actually, in an objective way, evaluate [the] letter ... That's a threat’” pic.twitter.com/59kyjIN46N — Ryan Saavedra (@RealSaavedra) October 13, 2019

According to Sen. Paul, the senators informed Ukraine, "If you don’t keep investigating Trump, we may reconsider our bipartisan support for your aid."

Sound familiar? That's the sort of quid pro quo Democrats are accusing Trump of when he called Ukrainian President Volodymyr Zelensky back in July. A whistleblower accused Trump of threatening to withhold military aid if Zelensky didn't agree to investigate his political opponent Hunter Biden. The White House released the phone transcript and, while it did show Trump ask about the Bidens, it did not corroborate the quid pro quo narrative.

"If anything is consistent here, it’s that both parties have tried to involve themselves in Ukraine," Paul observed.

It piqued Donald Trump Jr.'s interest. He suggested it sounded fishy enough to warrant a separate investigation, and cc'd a few relevant parties.

Someone needs to "objectively evaluate" that Democrat-authored letter, Paul stated.