Critics of Trump note that no crime is necessary to impeach the president. While that's true, it speaks to how weak the Democrats' case against Trump is.

President Donald Trump joined Bill Clinton and Andrew Johnson in the club of impeached presidents Wednesday night. Like the other two, Trump will be acquitted by the Senate once the articles of impeachment are delivered.

The case for Trump’s impeachment is the weakest of the three. If we include Richard Nixon, who resigned on his way to impeachment, it’s the weakest of the four. Here’s why.

1. No Actual Crime

Previous impeachments at least had a crime. Andrew Johnson was the first U.S. president to be impeached. He faced 11 articles of impeachment, mostly built around his violation of the Tenure of Office Act of 1867. That act limited the power of presidents to fire employees in Senate-approved positions without the consent of the Senate. While the law was blatantly unconstitutional, Johnson did violate it by getting rid of Secretary of War Edwin Stanton.

Clinton was impeached for actual crimes that would get the rest of us in a whole lot of trouble. He was impeached for lying to a grand jury about his sexual relationship with Monica Lewinsky, false statements he’d made in an earlier deposition, and false statements he allowed his attorney to make about witness tampering. He was also impeached for obstructing justice in a case filed against him by encouraging Lewinsky to make a false statement and give false testimony, by hiding gifts he’d given to her, getting her a job in exchange for favorable testimony, attempted witness tampering with his secretary, and making false and misleading statements to jurors.

Nixon would have been impeached for obstructing an investigation into the unlawful break-in by his Committee to Re-Elect the President at the Watergate building and using the IRS and other agencies to violate others’ privacy.

By contrast, President Trump was not impeached for any recognizable crime. Critics of Trump note that no crime is necessary to impeach the president. While that’s true, it speaks to how weak the Democrats’ case against Trump is.

2. Punishing Trump for Exercising Constitutional Privileges

Trump is being impeached for abusing his power and for obstructing Congress. The first charge relates to complaints with how Trump handled foreign policy with Ukraine. In a friendly phone call with the Ukraine president, Trump asked for help investigating corruption issues in the country. Since some of the corruption touched on the family of Joe Biden, Democrats say Trump abused his power since Biden may be his 2020 election opponent.

Biden was the Obama administration’s point man in Ukraine when his son, Hunter, who had no expertise in the region or industry, was being paid $80,000 a month to sit on the board of an energy concern there. Setting aside that charge, the second charge is more troubling.

Democrats say that Trump’s decision to exercise his constitutional privilege to protect executive communication means he should be removed from office. That’s their second charge — obstruction of Congress. Many presidents have battled with Congress over their executive privilege and what it covers, but the idea that the debate is cause for impeachment is remarkably weak. If President Trump had defied a court order to turn over documents, that would make for a stronger case. But that hasn’t happened.

3. Bipartisan Opposition Instead of Bipartisan Support

Previous impeachments had bipartisan support. In Trump’s case, not a single Republican supported impeachment and several Democrats declined to support it. This is a remarkable turn of events from the time that impeachment first began to be lobbied for. The media and others in the resistance pushed impeachment within hours of Trump’s inauguration.

The initial plan was to spin up a special counsel that would deliver a report on collusion with Russia to steal the election. That dream fizzled with the inability to find a single American, much less anyone affiliated with the Trump campaign, who had done so. But at its onset, the plan allegedly had Republican support. Now, no Republicans are joining Rep. Adam Schiff and Rep. Jerry Nadler in their impeachment goals.

The plan was clearly to start with limited Republican support and grow from there. Instead, there was no growth in the ranks of Republican support. And while high percentages of Americans have told pollsters for months that they would like the Bad Orange Man impeached, there was no movement in those polls toward more support. Even more surprisingly, Trump’s approval ratings went up. This shows us that the bipartisan growth and momentum that was needed isn’t happening.

4. Failure to Do the Work

Previous impeachments and impeachment efforts required a great deal of work from congressional and other investigators. Some spent years investigating matters before bringing them to Congress.

In this case, impeachment was built entirely around a late July phone call with Ukraine’s president. The original impeachment effort was to say that the phone call violated campaign finance law. That charge morphed into claims of bribery, extortion, and obstruction of justice. By the time two articles of impeachment were drafted, it was clear that the case had lost focus.

After the vote, some Democrats suggested that the House could keep investigating the matter. Speaker of the House Nancy Pelosi herself signaled a lack of confidence in her members’ work when she said that the House might not even send the articles over to the Senate for a trial. She claimed that was because of how Senate Majority Leader Mitch McConnell planned to run the trial, but he said he would use the same rules that were used in the Clinton trial.

House members also coordinated with Senate Minority Leader Chuck Schumer on how the Senate trial should go. He told television cameras that he would like to call witnesses to further investigate the underlying matter. This would only be necessary if the House didn’t bother to complete their investigation because they were rushing.

Democrats hope to tarnish Trump heading into 2020. While they have done their best, what they’ve mostly provided is the weakest impeachment case in U.S. history.