We are fast approaching the halfway point between the last presidential election and the next presidential election, which makes right now a good time to think about how the events of 2016 will set precedent for 2020.

On May 16, 2018, The New York Times revealed that, in August of 2016, the FBI opened an investigation into the Trump campaign code named “Crossfire Hurricane.” The investigation appears to have employed a handful of FBI agents and some of the powerful tools of counterintelligence.

Accusing a political figure of a crime is, unfortunately, nothing new. The pretext is easy to manufacture. In the case of the Russia collusion story, Clinton appears to have hired Fusion GPS to concoct the pretext.

What is new is the FBI’s apparent cooperation with such partisan accusations — including the use of at least one informant and a wiretap warrant against the opposition’s campaign staff.

Looking ahead to 2020, appointees of President Donald Trump now head all of the intelligence agencies, the Department of Justice and the FBI. If it hasn’t happened already, soon the Trump 2020 campaign will very likely begin gearing up for a serious run for reelection.

Apologists for the Trump campaign surveillance need to ask themselves a simple question: How will they react if Trump turns to the FBI to push a Trumpian version of “Crossfire Hurricane”?

For Candidate Hillary Clinton, the pretext for investigation was Russia collusion. For Trump’s 2020 political opponent, who knows? To illustrate how easily a pretext for a criminal investigation can be conceived, let’s review history. An argument can be made that nearly all candidates for higher elected office end up fending off a criminal accusation at some point.

This is by no means an exhaustive list:

1. From 2015-2016, Hillary Clinton was investigated for mishandling classified information and inappropriately steering favors from the Department of State to wealthy Clinton Foundation donors.

2. In 2016-18, former Candidate Bernie Sanders and his wife were investigated for loan fraud.

3. In 2015, Marco Rubio, a candidate in the 2016 presidential election, was investigated for improper expenditures while in the Florida State House.

4. In 2016, two “watchdog” public interest groups called for candidate Jeb Bush to be investigated for breaking campaign finance laws.

5. In 2016, The New York Times urged an investigation of candidate Ted Cruz for failing to report a loan from Goldman Sachs.

6. Chris Christie’s 2016 presidential ambitions and later consideration for a vice president were perhaps dashed by an investigation into whether he or his staffers purposely closed a traffic lane to retaliate against a political opponent.

7. Martin O’Malley, briefly a candidate for the 2016 Democratic presidential nomination, was investigatedfor buying discounted furniture for the governor’s mansion.

8. Days before the 2012 election, Republican candidate Mitt Romney was accusedof running a company that stole millions of dollars from Medicare.

9. Republican candidate New Gingrich’s 2012 presidential campaign was partially hampered by an ethics investigation.

10. In 2012, candidate Mitt Romney called for a special counsel to investigate whether the Obama administration leaked classified information to help Obama’s 2012 presidential reelection bid.

11. In 2012, candidate Rick Santorum was investigated for belonging to the Board of Directors of a company that was accused of Medicaid fraud.

12. In 2008, we were reminded that John McCain played a prominent role in the 1989-1991 criminal savings-and-loan scandal.

13. In 2008, candidate for vice president Sarah Palin was investigated for attempting to fire a brother-in-law state trooper.

14. Also in 2008, Barrack Obama was outed for having a close friendship with Tony Rezko, a felon convicted on bribery charges who subsidized the purchase of Obama’s home.

15. In 2008, Senator Ted Stevens lost his Senate election after being wrongfully convicted of federal ethics charges. Two of the prosecutors received suspensions for their own ethics violations in the case but these suspensions were later overturned for procedural reasons.

16. From 2005-2014, Tom DeLay, former House Majority Leader, was wrongfully prosecuted and ultimately exonerated for “money laundering” and other violations. The prosecutions nevertheless forced him from office.

Even without knowing the identity of the Democrat whom President Trump will face in 2020, it’s a fairly safe bet that there will be some kind of criminal investigation against this opponent at some point.

So, President Trump might ask, why not use a pen register to track calls of campaign attorneys? Or a no-knock warrant of a private attorney’s legal office and home to investigate a potential campaign finance violation? Or get a warrant to wiretap at least one campaign aid? Or use an FBI “informant” to advise or join the opposition’s campaign’s staff? And then, why not leak, leak, leak, leak, and leak to tilt the election and/or destabilize the opponent if he wins?

There’s an often forgotten statute, 5 U.S.C. § 7323(a)(1) which prohibits an employee from using “his official authority or influence for the purpose of interfering with or affecting the result of an election.” The statute covers all government officials, including members of the intelligence community and the Department of Justice.

There’s no Trump exception to this law.

Again, I turn to the apologists for the surveillance of the Trump campaign: You must condemn the politically-motivated use of law enforcement tools against Trump in 2016 or lose all moral authority to oppose President Trump if he employs the same tactics in the 2020 presidential election.

The author works in Kansas City, Missouri as an attorney specializing in employment and public administration law. He is a graduate of the University of Kansas. He blogs at Mill Street Gazette. The name Adam Mill is a pseudonym.

The views and opinions expressed in this commentary are those of the author and do not reflect the official position of The Daily Caller.