I'm sorry Tom Harkin is not going to run for reelection in 2014. I respect his reasons. Time is "fleeting," as the 73-year-old Senator said in announcing his decision. And he will have served 40 years in Congress by then, and I acknowledge the validity of his point that he should let other people get a chance to serve.
But we'll sorely miss him and his courage.
Even before he was elected to Congress, he served as a staffer on the House Select Committee on U.S. Involvement in Southeast Asia. In 1970, he went with members of that committee to Vietnam, and he made public some embarrassing information about the "tiger cages" where our allies in the South Vietnamese government were torturing prisoners. Harkin actually had visited the prison and talked with the prisoners himself. He took pictures of the tiger cages, and, against the express wishes of his Congressman, he delivered them to Life magazine, which published them.
He wrote about the experience in a cover story for The Progressive in October 1970 called "Vietnam Whitewash: The Congressional Jury That Convicted Itself." He said he couldn't ignore the voices of the prisoners in the tiger cages begging him to tell their stories.
And he also said: "One man can stand up and make a difference."
Well, Tom Harkin has stood up repeatedly, and repeatedly he has made a difference.
He made a difference in the late 1970s, when he denounced U.S. support for Indonesia's invasion of East Timor.
He made a difference in the 1980s, when he opposed U.S. support for the contras.
He made a huge difference in 1990 when he wrote the Americans with Disabilities Act.
He ran for President in 1992 in the Democratic Party but unfortunately lost to some obscure governor from Arkansas. But he made a difference by refusing to append the word "neo" to his brand of liberalism.
And he kept making a difference.
Tom Harkin has repeatedly made a difference by supporting abortion rights.
He has repeatedly made a difference by supporting farmers.
Tom Harkin has repeatedly made a difference by supporting workers' rights, demanding an increase in the minimum wage and better working conditions.
He has repeatedly made a difference by supporting stem cell research.
He has repeatedly made a difference by standing up for civil liberties.
He himself was the victim of a crude McCarthyite attack when he was running for reelection in 2008.
His Republican opponent, Christopher Reed, called him "the Tokyo Rose of Al Qaeda and Middle East terrorism."
Those remarks came in a forum on October 30 broadcast on Iowa public TV and sponsored by the Des Moines Register, the paper reported.
Reed also said that Harkin was "anti-American" and was "providing aid and comfort to the enemy," which is the constitutional definition of treason, a crime punishable by death.
Harkin said the comments were out of line and predicted: "It's going to hurt him," he told the paper.
At the taping, Harkin was heard to say, directly to Reed: "You're a nice young man, and I thought you had a political future ahead of you. But that just ended your political career right there."
Harkin whupped Reed 62.5 percent to 37.5 percent.
In one of his most recent votes, Harkin showed his independence and his dedication to principle. He was the only Democrat to vote against the agreement on the fiscal cliff.
"We find ourselves voting on an agreement that fails to address our number one priority -- creating good, middle class jobs in Iowa and throughout the country," he said. "Further, it does not generate the revenue necessary for the country to meet its needs for everything from education for our children, to job training, to other critical supports for the middle class. The deal also makes tax benefits for high income earners permanent, while tax benefits designed to help those of modest means and the middle class are only extended for five years. In essence, this agreement locks in a tax structure that is grossly unfair to middle class Americans, one which provides permanent tax assistance to wealthy Americans, and only temporary relief to everyone else."
That's the Tom Harkin I know and love.
And that's the Tom Harkin I'm going to miss so much.
P.S. You can see Harkin discussing the tiger cages and much more in a talk he gave at Fighting Bob Fest in Wisconsin in September 2009. Here's the video:
If you liked this story by Matthew Rothschild, the editor of The Progressive magazine, check out his story "Obama in the Shadow of Martin Luther King." 
 Follow Matthew Rothschild @mattrothschild  on Twitter.