Editor’s Note: Julian Zelizer, a CNN political analyst, is a professor of history and public affairs at Princeton University and author of the forthcoming book, “Burning Down the House: Newt Gingrich, the Fall of a Speaker, and the Rise of the New Republican Party.” Follow him on Twitter: @julianzelizer. The views expressed in this commentary are his own. View more opinion at CNN.

CNN  — 

The first week of impeachment public hearings was devastating for President Donald Trump. The House Intelligence Committee heard testimony from foreign service officials deeply troubled by the administration’s shadow policymaking cabal, headed by Rudy Giuliani, that withheld vital foreign aid in exchange for campaign support.

The week ended with former Ukraine Ambassador Marie Yovanovitch recounting the vicious smear campaign that helped lead to her being drummed out of her job. As she spoke, the President confirmed his willingness to attack her this way via live tweets.

Julian Zelizer

As if that were not bad enough, David Holmes, an aide to the top US diplomat in Ukraine, William Taylor, ended the day behind closed doors explaining, according to his opening statement, how he overheard the President speaking loudly on the phone with Ambassador Gordon Sondland in a restaurant in Kiev about the investigations related to Hunter Biden and conspiracy theories about the origins of the Russia investigation.

In other words, everyone has been confirming the report of the whistleblower. Republicans have been left to offer faux complaints about the process and to suggest that all of the bad things that are being reported are based on hearsay.

We have no idea how the impeachment process will turn out. Any good student of history realizes just how uncertain the politics of impeachment can be. Solid predictions often turn out to be untrue. Republicans would always stand by Richard Nixon, or so the experts said in January 1974, until they no longer did. While we are most likely looking at the House voting in favor of several articles of impeachment against President Trump and the Senate voting to let President Trump remain in office, things can change quickly.

But one thing seems certain: The predicted political backlash over impeachment that Democrats were frightened about will not be taking place. Republicans won’t have an easy time employing the standard partisan witch hunt argument.

The case that House Democrats are making to the public about how Trump and his inner circle abused presidential power, skewed foreign policy for personal gain and then tried to hide and obstruct the investigation that followed the revelations is becoming overwhelming. The President himself keeps helping Democrats build their case through his tweets and public statements. His inclination to attack and seek to destroy might work in less frenzied times but now it registers differently in the middle of a formal investigation.

House Democrats might never be able to turn a single Republican vote in the House or Senate. Any Republican who dares to buck the party line probably won’t find any room left for them in the party; just look at Michigan’s Justin Amash.

However, as a result of the impeachment, Democrats will be able to vote in favor of articles of impeachment with a rock-solid case to support their decision and a clear picture for the public about why the party feels the need to take these steps.

While the impeachment of President Bill Clinton revolved around his perjuring himself about his relationship with an intern, this investigation is about the corruption of foreign policy. This week, Speaker Nancy Pelosi started to speak openly about bribery.

The congressional hearings are shifting the conversation away from the question of whether this entire process was necessary toward what is the best solution – impeaching and removing the President or waiting for the election. That is a debate that is pretty safe for Democrats to have.

For outside the most loyal circles of Republican politics, the hearings will allow the Democrats to position themselves as serious public servants trying to figure out what to do in an extraordinarily difficult and dangerous situation where the President has essentially forced their hand into taking action. Democrats are governing; Republicans are grandstanding.

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    If the hearings continue along these lines and a political backlash against the impeachment process never happens, Republicans will find themselves with an extremely damaged ticket in 2020. The articles of impeachment will be damning.

    President Trump would become the first President seeking reelection after having been impeached. With a President already unpopular in the polls, Republicans will be courting voters with a candidate who has abused his power in serious ways.

    Whoever the Democratic candidate is, his or her party will be able to make this a central issue as they define the choices that voters face when choosing the leader they want to inhabit the Oval Office for the next four years.