A whistleblower’s complaint over President Donald Trump’s interactions with a foreign leader is testing the political and practical power Democrats can use against a Republican in the White House who so brazenly ignores protocol and presidential norms. Democrats were unanimous in their condemnation of Trump for going to extraordinary lengths to tear down a chief political rival by asking the new leader of Ukraine to investigate the son of former Vice President Joe Biden. But even as calls for impeachment amplified – Elizabeth Warren blasted Congress as “complicit” in Trump’s transgressions – there were no signs that House Speaker Nancy Pelosi would move quickly to try to remove the president. Allies of Biden, the early front-runner in the Democratic presidential primary, seized on the developments to portray him as the candidate Trump least wants to face next fall. But the controversy could just as easily revive interest in the business activities of Biden’s son, which would do little to further his campaign. Taken together, the developments bear a striking resemblance to the tumult of the 2016 campaign, in which Trump was accused of enlisting a foreign power to help him win an election. The president on Saturday denied any wrongdoing, and his most vocal allies and critics were energized. Political operatives in both parties suggested that for many increasingly numb to a constant sense of crisis, the fresh explosion of political drama may not seem so alarming. One thing is becoming clear: Trump is more than willing to cast aside norms to gain a political advantage. Jesse Ferguson, a Democratic strategist and former top aide to Hillary Clinton, said the country “has to be ready for the president to try to weaponize the government against them in a way we’ve never seen before in American history.” The president on Saturday embraced the parallels to the 2016 campaign and predicted he would prevail again in 2020. Trump said the latest allegations from a government whistleblower are “just as ridiculous as the others,” branding it “the Ukraine Witch Hunt” – a nod to former special counsel Robert Mueller’s Russia probe, which he mocked as a “witch hunt.” “Will fail again!” Trump tweeted. The complaint from the intelligence community whistleblower is based on a series of events, including what sources now say is Trump’s conversation with Ukrainian President Volodymyr Zelenskiy. The conversation happened on July 25, just a day after Mueller wrapped up his own work by testifying on Capitol Hill. Trump urged Zelenskiy to probe the activities of Biden’s son Hunter, who had worked for a Ukrainian gas company, according to a person who was briefed on the call. For legal scholars and ethics watchdogs, the interaction between Trump and the foreign leader is seen as nothing less than a pressure campaign that cuts to the core of the nation’s public corruption and bribery laws. It came as the White House was holding up $250 million in military aid for Ukraine. Even if there was no quid-pro-quo from the president, the conversation could be seen by legal experts as improper. “It appears that the president might have used his official powers – in particular, perhaps the threat of withholding a quarter-billion dollars in military aid – to leverage a foreign government into helping him defeat a potential political opponent in the United States,” wrote lawyer George T. Conway III, who is married to a top Trump adviser, and Neal Katayal, a Georgetown University law professor and former acting solicitor general, in an op-ed in The Washington Post. “If Trump did that, it would be the ultimate impeachable act.” Campaigning in Iowa on Saturday, Joe Biden said the president “deserves to be investigated,” but he stopped short of calling for impeachment. “He’s using the abuse of power and every element of the presidency to try to do something to smear me,” Biden told reporters. Sen. Chris Coons, D-Del., said Trump’s actions show “Joe Biden is correctly perceived by President Trump as the greatest threat to his re-election.” It’s less clear whether the situation may ultimately hurt Biden, who has claimed the moral high ground in his 2020 campaign. When speaking about his experience as vice president, Biden often says he’s most proud of the lack of scandal during his eight years in the Obama White House. Trump’s allies hope that the focus on Biden’s involvement in Ukraine may begin to chip away at his squeaky clean image. “The longer we talk about what the Bidens did in Ukraine, the better,” said Barry Bennett, a former Trump campaign adviser, who dismissed those who believe Trump will pay a political price for the latest controversy. The questions about Hunter Biden have circulated for years, particularly in conservative circles, after he was hired in 2014 by Burisma Holdings, whose founder had been a political ally of Russia-friendly former Ukrainian President Viktor Yanukovych. At the time questions were raised about whether the Ukrainian firm was seeking to gain influence with the Obama administration through its employment of Joe Biden’s son. This year, Trump’s personal lawyer Rudolph Giuliani revived interest in the issue and said he reached out directly to the Ukrainian government. Joe Biden said he’s never spoken to his son about his overseas business dealings. Hunter Biden has denied the claims that he used his influence with his father to aid Burisma, saying the criticism is false and stoked by far-right political critics. While Sen. Warren and other Democrats say there’s no choice but to start impeachment proceedings, other Democrats have been reluctant to launch a process they say could scare away more moderate and centrist voters, especially for lawmakers in Congress. Pelosi showed no signs of moving off her position that Congress must continue to investigate the administration and not start impeachment proceedings unless the American public demands it. Instead, she said that Trump faces “repercussions” if the whistleblower’s allegations prove true and she said it’s time to change the law to make sure future presidents can be indicted for wrongdoing. Democratic strategist Jefrey Pollock, who was a pollster for former presidential candidate Kirsten Gillibrand, suggested that the latest explosive allegations against the Republican president would have little impact on the broader 2020 debate. “To date, no scandal has seemed to impact Donald Trump on its own,” Pollock said. “And the fact that this one involves a political rival I suspect is no different.”