Apropos of this Valentine's Day just past, there's a lot of flirting going on between the United States and Iran, leading some to day-dream of improved relations between the long-time foes.

Secretary of State Hillary Clinton said the two sides should "seek a better understanding of one another." President Barack Obama noted "direct engagement" is possible if Iran is willing to "unclench" its fist.

Even Iran proclaimed it's ready for dialogue, shockingly coming from hard-line President Mahmoud Ahmadinejad in a speech commemorating the Iranian Revolution's 30th anniversary.

An opening? Perhaps.

But better take a gander at the speed bumps and potholes that lie ahead on Lover's Lane.

Take Iran's nuclear program. It's undoubtedly a weapons program and has been spinning along unimpeded by a treaty, U.N. resolutions or punitive economic sanctions for years.

Iran's been clear it won't give up its nuclear program and, after more than six years of negotiating with the Europeans, there's proof of that conviction.

In fact, it's very likely Iran will have produced enough weapons-grade fissile material for at least one nuclear weapon this year.

Its space program, including a recent satellite launch, doesn't encourage calm either. Many believe their space effort (actually run by the military) is cover for a ballistic missile program.

And what about Iran's deep and abiding sponsorship of terrorism, a concept central to Iran's national security strategy?

Palestinian Hamas and Lebanese Hezbollah have served Tehran well as foils against Iran's enemies, especially Israel. Iran isn't likely to part company with them.

There are human rights issues, too, especially considering Tehran's recent nasty crackdown on the press, women and student groups.

And what about Iran itself? The collective leadership, led by Supreme Leader Ayatollah Ali Khamenei, isn't in full agreement on how to deal with the United States.

Some clerics fear that opening to the "Great Satan" will lead to their greatest fear - a counterrevolution by the elites and the young, who want a greater say in Iranian society.

Alternatively, since many Iranians want better ties with the U.S., Ahmadinejad could be feigning an easing of tensions to enhance his chances of winning re-election in June.

With time on its side, Iran might also be using a potential detente to try to put the brakes on an American or Israeli military strike on its nuclear program.

Another problem is the tortured history between the two countries - one marked by a CIA-supported coup, Islamic revolution, embassy hostages and terror attacks on military barracks, leading to much suspicion.

Talks in and of themselves aren't necessarily harmful as long as economic sanctions remain in place. Indeed, testing Tehran's diplomatic intentions through dialogue makes sense, even though Iran's real gripe is with the United States - not any particular White House.

A grand bargain, as some talk of, is sure to be elusive if not impossible. Though the couple may be making eyes at each other, they hold vastly different dreams.

While we should welcome better bilateral relations with Iran after 30 years of mutual hostility, Washington must ensure that any engagement protects and advances U.S. interests - not just Iran's.

(This op-ed originally appeared in The Boston Herald.)