Instead of humbly pulling back from his campaign to bully his political opponents after a flurry of negative editorials, Dick Durbin has doubled down on arrogance and constitutional ignorance.

In his response to the Chicago Tribune editorial, "Durbin's enemies list," the senior senator from Illinois refused to concede the obvious point: that he was bullying his political opponents and generally making a mockery of the First Amendment.

You'd think that after Durbin was caught targeting conservative groups in an earlier letter to the Internal Revenue Service, he'd be more cautious. To the contrary, Durbin has now sent 300 intimidating letters to donors of the free market advocacy group, American Legislative Exchange Council (ALEC). In his rebuttal to the Tribune editorial, Durbin stubbornly insists he has a right to donor information because he, as a public official, has to make certain public disclosures.

Durbin is confused. He works for us. The disclosures he makes are because the public has a right to vet the people who spend their tax dollars. The U.S. Supreme Court says that Durbin has no parallel right to vet donors of advocacy groups who are exercising their First Amendment rights. You'd think a senior senator would understand this elementary distinction.

Durbin also fails to reveal to the Tribune and other media outlets that he never complains about liberal advocacy groups he agrees with and certainly never sends them threatening letters. Durbin is paid to represent all of Illinois, not just those who share his belief in failed liberal philosophies.

Another troubling issue that the letters raise is where did Durbin acquire ALEC's donor list? That's an obvious unanswered question the Illinois and national news media ought to pursue.

It's bad enough that Durbin is a political bully who practices the crudest form of partisan politics. What is really sad is that such a longtime public official is arrogant enough to believe he has the authority to apportion the First Amendment to others according to their political beliefs.

It's time for Americans who believe in the First Amendment to stand up and fight back against this three-term tyrant and that is exactly what I plan to do in the months ahead.

Doug Truax is a West Point grad, an Army veteran, successful entrepreneur/businessman and a Republican candidate for U.S. Senate.