What should be a routine confirmation proves to be anything but.

A routine confirmation for U.S. ambassador should not be delayed by personal agendas.

Six months after President Barack Obama nominated Roberta Jacobson, the top U.S. diplomat for Latin America, to be ambassador to Mexico, she still hasn’t received U.S. Senate approval or even gone before its Foreign Relations Committee for a confirmation hearing.

Despite the importance of the U.S.-Mexico relationship and the fact that she is highly qualified for the job, two Cuban-American senators, Republican Marco Rubio of Florida and Democrat Bob Menendez of New Jersey, have put their personal agendas ahead of the country’s interests to prevent her nomination from moving forward.

Both senators are on the Foreign Relations Committee, where they have worked to stall Jacobson’s ascent because they don’t like the fact that as Assistant Secretary of State for Western Hemisphere Affairs she played a leading role in re-establishing diplomatic relations with Cuba.

It has long been obvious to most of the world that our Cold War policy of exclusion and embargo has failed, but Rubio, Menendez and fellow Cuban-American Sen. Ted Cruz of Texas steadfastly stand by it even as support fades in the broader Cuban-American population.

Rubio and Cruz, of course, are both seeking the Republican presidential nomination.

We respect that the families of all three were uprooted by the Castros’ 1959 revolution, and we do not support the Castro government, but personal feelings and political grudges must not take precedence over what’s best for the country.

The truth is that Mexico is much more important to the U.S. than Cuba. It is our third largest trading partner, behind China and Canada, has 100 million people and shares with us a 2,000-mile border that is controversial for the immigrants, drugs and guns that flow across it.

Houston has a large Mexican immigrant population and is a steady customer for goods and services in Mexico’s oil industry.

Many U.S. presidents have sent diplomatic novices to Mexico, but this increasingly complex relationship is best served by a veteran diplomat who understands the country, knows the issues and speaks the language — someone like Jacobson, in other words.

She has devoted her entire 30-year State Department career to Latin America, worked in embassies in Argentina and Peru, is considered an expert on Mexico and speaks fluent Spanish.

Washington-based Politico has reported that Jacobson may finally get a confirmation hearing this month and would likely be approved by the full committee, but that her appointment could be held up again in the full Senate. That would be a travesty.

We urge both senators from Texas, Cruz and John Cornyn, to support Jacobson and convince their colleagues to do the same. It is way past time for the Senate to act on this matter.