The senator's Web site boasts that his wife, Ruth Harkin, is the highest-ranking woman at United Technologies Corp. Her official title: senior vice president, international affairs and government relations.
United Technologies (UTC), one of the largest corporations in the world, receives more than $3 billion in annual revenues from U.S. government contracts.
Much of this money comes from the purchase of UTC's Blackhawk helicopter, a vital component of the U.S. military arsenal.
UTC will get more than $200 million for 18 Blackhawks as part of the recently passed Colombia aid package. Another $189 million has been allocated for additional Blackhawk purchases by the Pentagon - almost triple the department's initial request.
This funding, and the inclusion of Blackhawks in the aid package, has some Harkin supporters wondering if his wife's job and the senator's influence are a bad combination.
"I'm just disgusted with Harkin," says Don Gruber, a retired minister and member of Pastors for Peace in Iowa. "Harkin particularly thinks he's a socially minded person. I wouldn't rank him too high anymore. He's a corporate guy." Scott Seligman, public relations director for UTC, says Ruth Harkin had nothing to do with the Colombia aid package and that accusations of undue influence are unfounded.
However, when an early version of the Colombia aid package excluded the Blackhawks, Ruth Harkin spoke publicly about her disappointment.
She told the Hartford Courant, "We will continue to work closely with key members of the House and Senate when they go to conference to make sure Colombia gets the Blackhawks they need to win the war on drugs."
Despite this, Seligman insists Ruth Harkin did not work on securing the Blackhawks for the Colombia aid package, and that her position affords her no influence over government matters.
"Ruth is not a lobbyist," he says. "The lobbyists report to Ruth, but she did not lobby that bill.
"We have very little to do with (Senator) Harkin's office. There's really no substance to the charge. But I can understand why someone might ask."
Senator Harkin's office claims he is solidly in favor of human-rights measures and opposes military assistance to governments with a poor history in this area. His record seems to bear this out.
He voted twice to severely cut the Colombian aid package, and once to transfer money from the military-aid program, which includes the Blackhawk money, to domestic substance-abuse and mental-health services.
"If we can provide millions of dollars to fight drugs in Colombia, we should be able to find the money to fight drugs in our own backyard," a statement from Harkin's office reads.
Harkin appears squeaky clean. But for some, the potential for corruption is enough to warrant concern.
Despite Harkin's solid voting record against the military portion of the package, he voted for an amendment that would have made room for Blackhawk helicopters when earlier versions failed to do so.
Originally, the aid package called for the purchase of Huey helicopters. But the Dodd Amendment would have opened the possibility of including Blackhawks in the deal.
Harkin voted against the aid package after this measure failed. After the Blackhawks somehow worked their way back into the package, he voted with the 96-vote majority in favor of the final appropriations bill. This included an aid package worth more than $200 million for UTC.
Despite Harkin's promises that his opposition to military aid is morally based, some are not convinced.
"In the face of it, I don't like it," says Larry Larson, a former Iowa House member and Harkin supporter. "It may be legal, but it sounds kind of dubious to me. I personally don't think it's right."
"It's not an uncommon situation," says Mack Shelley, an Iowa State University political-science professor since 1979. "This kind of thing happens fairly often when you have two spouses who are politically prominent, but it is a major problem. Congress is trying to limit access to lobbying."
Federal officials are prevented from actively lobbying for one year after leaving office - hardly a corruption-prevention measure. And there are no lobbying restrictions on spouses of politicians.
The senator's office says his committee vote against the Colombia aid package was a result of its failure to protect human rights and provide funds for the cleanup of methamphetamine labs in the United States. Harkin was not present at the full Senate vote, when the Colombia package was attached to the military spending bill.
Government is so influenced by corporate America that Gruber is no longer sure any politician, even the squeaky-clean Harkin, can be trusted. There's no way for him to know whether Harkin's human-rights position is sincere, or merely a smokescreen to disguise voting in the interest of his wife's company. "So much of this goes on, it's hard to keep track of."
A shorter version of this article originally appeared in Cityview, the alternative newsweekly of Des Moines.