Don't fall for Republican presidential nominee Donald Trump's smirking dismissal of his illegal campaign contribution to a political action committee supporting Florida's attorney general. His campaign calls it a "clerical error," but it was an illegal contribution, and he knows it.

Under the tax code, non-profit foundations are not allowed to make political contributions. But the Internal Revenue Service determined that the Trump Foundation illegally made a $25,000 contribution to And Justice for All, a group supporting Florida Attorney General Pam Bondi, and fined the foundation $2,500. Trump's foundation paid the fine, a clear acknowledgment that the gift was illegal.

Trump's smirk is an expression of his casual relationship with a system rigged to favor people who shower politicians with money to get what they want. Trump even brags about it. Typical of his comments is what he said to the Wall Street Journal in July 2015: "As a businessman and a very substantial donor to very important people, when you give, they do whatever the hell you want them to do."

The Trump Foundation contribution raises questions about whether other laws were broken, including the prohibition against self-dealing, which is using foundation funds to benefit a foundation principal.

Soon after New York Attorney General Eric Schneiderman filed a lawsuit in 2013 against Trump and Trump University alleging fraudulent practices, including making educational promises it didn't keep, the Florida Attorney General's Office confirmed it was considering similar prosecution.

A few days later, however, Trump's foundation gave the illegal $25,000 contribution to the Bondi PAC. She then quickly lost interest in pursuing Trump University even though her office received numerous complaints from Floridians about the sham operation. Bondi has made her self-serving predilections even more clear by endorsing Trump and campaigning for him.

Both Trump and Bondi are scrambling to put this scandal behind them, but voters shouldn't let them. Bondi's ethical problems will be dealt with in Florida, where voters in that state can choose a better attorney general. More concerning is the behavior of Trump, a man who would be president but blatantly takes advantage of weak and deeply flawed ethics rules.

A recent Washington Post investigation uncovered Trump's use of the foundation as a reflecting pool for his narcissism. He reportedly takes other people's money and donates it as his own, taking full credit to further the Trump trademark, his most bankable asset. One can only imagine what someone with that attitude would do with the U.S. treasury.

With all the distractions and distortions in this campaign, a candidate's past behavior is a good guide to what he or she would be like in office. It seems clear that Trump used his foundation to protect his university from charges that it was taking real money from real people and producing fake results.

Trump's reputation for taking care of himself at the expense of others may be his biggest obstacle to becoming president. He can't afford more stories that suggest he would pay off an attorney general to avoid an investigation.