Competitive Republican primaries for U.S. Senate don't come along often in Kansas, so the race between 1st District Congressman Jerry Moran and 4th District Congressman Todd Tiahrt to fill the spot of retiring U.S. Sen. Sam Brownback is receiving the most statewide attention of any tilt that will be on the Aug. 5 ballot. And deservedly so, because whomever wins the GOP primary has an excellent chance of not only winning the seat but of holding it for a long, long time. Why? Because while the past is not always prologue, it can be a good guide, and in Kansas a Democrat hasn't won a Senate seat since 1932. Also, with the exception of the Bob Dole and Bill Roy race in 1974, voters in the Sunflower state have shown little inclination to not re-elect an elected incumbent. In short, whoever wins this GOP Senate primary might have little to no electoral incentive to seriously campaign for votes again.

Given the importance of the race, the lack of clear policy distinctions expressed so far between the two candidates is surprising. In their most recent joint appearance, Tiahrt and Moran were asked to discuss what they saw as the main differences between them and both answered by emphasizing their background and personal characteristics. The candidates failed to mention their serious policy difference on an issue that might sound obscure to Kansans but has in fact had a large impact on the state for a half century: U.S. policy toward Cuba.

Beginning in 1960, U.S. policy towards Cuba has been to put serious restrictions on bilateral trade and travel. The result -- known in Cuba as "El Bloqueo," or "The Blockade" -- is that current U.S. policy effectively forbids almost all Americans to travel to Cuba (and vice-versa) and makes exporting U.S. goods to Cuba difficult. The policy was originally put in place as punishment for Fidel Castro's nationalization of privately owned properties after the Cuban revolution but quickly morphed into punishment for being allied with the Soviet Union during the Cold War. After the collapse of the Soviet Union the sanctions were tightened in the 1990s with the intention of strangling the Castro regime into changing its one-party political system.

Moran told me straight out that the policy had been a failure.

"After nearly 50 years we should try another way," he said. "I've come to the conclusion that we have the ability to change Cuba through contact with us. Opening up travel and economic opportunities for Americans in Cuba increases the chance the government of Cuba will change. And it will allow Kansas farmers to sell their products and gain a market."

Tiahrt told me he strongly disagrees.

"I'm for free trade, just not with Cuba. They're a state-sponsor of terrorism, they don't pay their bills, and trade with Cuba will largely benefit the Castro regime. With expanded trade and travel we would just be funding the Castro brothers and the Cuban communist party. We should not change our policies without seeing any changes from them."

What's not debatable is that the blockade has had an impact on the state. Beyond restricting Kansans from freely traveling or studying where they wish, the policy has impeded access to a market for the state's agricultural producers. In 2009, Cuba spent close to $2 billion on agricultural imports. With Cuba's proximity to the U.S., some experts estimate if the blockade were lifted, nearly two-thirds of Cuba's imports could come from the United States.

So what on the surface seems like an irrelevant difference on a policy held over from the Cold War in fact has real-world consequences for Kansas' economy.

Given the economic potential for the state, there's no reason "El Bloqueo" shouldn't play a prominent role in a Moran-Tiahrt Senate primary that otherwise might be focused on personal characteristics rather than policy debates.

Bob Beatty: Dr. Bob Beatty is a political scientist and political analyst for

KSNT-27 News in Topeka.