At first glance, it doesn't look like a fair fight: Iran's hard-line regime vs. three American moms determined to bring their imprisoned children home.

But the Iranians asked for it. If we had to bet, our money would be on the mothers of three hikers taken into custody last July in northeast Iraq near the Iranian border. May their mission be a successful one.

There's been precious little progress in relieving the nearly 10-month-long plight of former Minnesotan Shane Bauer, 27, and his friends Sarah Shourd, 31, and Josh Fattal, 27, who are believed to be held in Tehran's hellish Evin Prison. But today, Cindy Hickey of Pine City, Minn., and the mothers of Shourd and Fattal are expected to touch down in Tehran in a bid not only to see their children but to free them. The mothers' arrival is easily the most positive development in the hikers' harrowing ordeal.

Roxana Saberi, a North Dakotan and journalist who was detained in Iran in 2009 on espionage charges, walked out of Evin Prison after about four months. May 27 will mark the hikers' 300th day in Iranian custody.

Why they're jailed has never been clear. Iranian officials have mentioned spying, but have never backed that up with evidence or charges. The only thing Iran has on the three is that they may have made a wrong turn when hiking to a scenic waterfall in Iraq's Kurdish area and accidentally crossed an unmarked border.

Should they have been more careful? Absolutely. They knowingly ventured into an area bordering one of the world's most notorious regimes. The risks were high for themselves, their families and even their country if they mistakenly took even a few wrong steps. Iran has a history of seizing Westerners, using them as bargaining chips and staging their release for maximum public-relations benefit.

Still, these three daredevil tourists hardly deserve lengthy imprisonment for this transgression. It's outrageous that they have been jailed this long. Bauer, Shourd and Fattal are no longer being punished. They're being held hostage.

Their mothers' visit to Tehran is a time for hope and action. Hickey, Laura Fattal and Nora Shourd have been smart, vocal advocates. With the help of friends and family, they've waged an Internet campaign to keep this case high-profile. These media-savvy moms understand Iran's global image problems and how those issues might be used to free their sons and daughter.

But they need help from those back home. Supporters need to write or e-mail Iranian officials and let them know that imprisoning the hikers longer accomplishes nothing. Iranians have made their point about being tough on the United States and being able to defend their borders. They've also accomplished a high-impact airing of their concerns about spies in Iran.

But Iranians also need to understand that any images of tearful mothers leaving empty-handed, particularly any broadcast close to the June anniversary of the bloody election riots last year in Iran, will only reinforce the regime's reputation as a lawless rogue.

So far, quiet diplomacy has been the main mechanism for seeking the hikers' release. If they don't go home with their moms soon, U.S. officials must shift gears and wage an intensified public campaign to shame Iran into doing the right thing.