U.S. Sen. Bernie Sanders on Tuesday repeated his support for an impeachment inquiry against Republican President Donald Trump, calling him the “most corrupt president” in modern U.S. history and contending there is already evidence suggesting the president has committed “impeachable offenses.”

Sanders called upon the House Judiciary Committee to demand all of the information from the Trump administration needed and move forward with an investigation, saying the American people are “sick and tired” of a president who “believes … that he is above the law.”

“Enough is enough,” Sanders said, drawing applause from roughly a dozen organized labor supporters attending a campaign event in Davenport.

But Sanders stopped short of committing to cast a vote in the Senate removing the president from office, saying it would be “irresponsible” to take that position before the impeachment process is finished. Calling himself “old-fashioned,” Sanders said he wants to review the findings and see the process play out before making a decision to that end.

Sanders gave his remarks Tuesday afternoon. A few hours later, U.S. House Speaker Nancy Pelosi announced the beginning of a formal impeachment inquiry in the House.

Pelosi had brushed off earlier calls for Trump’s impeachment, citing the political consequences that may carry for the Democratic Party. But she reversed course Tuesday, saying during a nationally televised press statement on CNN that “the president must be held accountable” and “no one is above the law.”

Earlier calls for impeachment centered on allegations that Trump’s 2016 presidential campaign conspired with Russian government officials to sway the election and that Trump tried to halt the subsequent investigation led by Special Counsel Robert Mueller. Many Democrats, including Pelosi, questioned the benefits of pursuing impeachment at that time.

But a renewed push for impeachment has emerged following recent reports that Trump may have withheld aid to Ukraine as leverage to convince Ukranian President Volodymyr Zelensky to investigate Hunter Biden — the son of former Vice President Joe Biden, a leading 2020 candidate — for the purpose of finding “dirt” that could harm the elder Biden politically. An anonymous whistleblower alerted the inspector general for the intelligence community to a phone call that took place between Trump and Ukraine’s leader in July, where Biden was discussed.

For his part, Trump has denied wrongdoing and repeatedly dismissed the concept of impeachment as a politically motivated “witch hunt.” In a pair of Twitter posts on Tuesday, the president said Democrats are simply focused on hurting him and the Republican Party at their own expense.

“You will see it was a very friendly and totally appropriate call,” the president said of his conversation with Ukraine’s president in the tweet. “No pressure and, unlike Joe Biden and his son, NO quid pro quo! This is nothing more than a continuation of the Greatest and most Destructive Witch Hunt of all time!”

Even if the House eventually approves articles of impeachment against Trump, his removal from office appears unlikely.

The U.S. Senate is split with 53 Republicans to 45 Democrats and two Independent Party members (including Sanders) who tend to vote alongside Democrats. The U.S. Constitution requires support of 67 senators to actually remove a sitting president.

Meanwhile, Sanders said Tuesday that it appears “the House has no choice” but to begin that investigation considering the allegations. But Sanders also added that there is a possibility Trump could use a failed removal attempt as a talking point by declaring himself “vindicated.” 

Sanders added that he hopes Republican colleagues in the Senate will “take a hard look at the evidence” that comes from a formal impeachment investigation and not react in a “knee-jerk way to protect the president.”

In Davenport, Sanders promoted endorsements from dozens of union labor activists as he seeks to gain ground in Iowa, the first-in-the-nation-caucus state whose presidential nominating process winnows the field of White House-seeking candidates every four years.

Standing along with several union labor folks in Davenport’s Duck Creek Lodge, Sanders touted his proposed Workplace Democracy Plan. That proposal, he said, would dramatically expand union membership by creating penalties for private-sector companies that fail to negotiate with unions in good faith or attempt to move operations out of country as a way to avoid the new federal regulations.

Sanders’ campaign also released details of a plan to tax the wealthiest Americans at a staggered rate beginning with a 1% tax on those worth more than $32 million. The proposed “Tax on Extreme Wealth” would max out with an annual 8% tax on wealth over $10 billion.

Democratic rival U.S. Sen. Elizabeth Warren, whose campaign also is centered on the concept of redistributing wealth, has touted a similar plan that calls for a 2% tax on households worth more than $50 million.