For months, certain lawmakers in Washington have tried to block Pentagon investments in alternative energy — investments that would reduce our military’s dependence on imported oil.

As election season ramps up, Congress should stop playing politics with this issue, and support the Pentagon’s efforts to invest in a secure energy future for our fighting forces.

Secretary of the Navy Ray Mabus has helped lead the U.S. military’s push toward renewable energy sources that can make our energy supply more secure, save taxpayer money and protect the lives of servicemen and women. This month, the Navy is participating in a major international exercise using cruisers, destroyers and jets powered by a biofuel-petroleum blend.

Maine will be watching: Maine’s biomass and shipbuilding industries and Portsmouth Naval Shipyard are all affected by the Navy’s increasing investments in biofuels and other renewable energy sources.

In a shot across the bow at the Navy’s innovative plans, however, a coalition of 14 congressional Republicans sent Mabus a letter opposing “an effort to ‘green’ the Navy just for the sake of greening the Navy.”

The letter suggests that the Navy’s investment in alternative energy has nothing to do with “winning wars, deterring aggression and maintaining freedom of the seas,” and therefore represents “dollar(s) wasted.”

The Republican-controlled House of Representatives then passed a measure to prohibit the Pentagon from buying alternative fuels that are more expensive than traditional ones. The Senate Armed Services Committee approved a similar measure.

If made into law, these provisions would quash the Navy’s scheduled exercise and confound its broader program to secure its energy supply.

This would be a shame. To date, U.S. proven and strategic energy reserves cannot meet our domestic needs. As Mabus points out, our reliance on fossil fuels makes us vulnerable to price shocks in a volatile global market. In fiscal year 2012 alone, increases in the price per barrel of oil raised the Navy’s fuel bill by more than $1 billion.

This isn’t just a problem for the Navy. The comptroller of the Department of Defense reports that the department’s annual fuel bill increases by $130 million for every dollar increase in the cost per barrel of oil.

Paying that bill out of Defense operations funds means that servicemen and women must “steam less, fly less and train less,” Mabus said. Preventing the Navy from developing alternative fuel sources only serves to weaken our military readiness.

Our military services use alternative energy technologies because they allow us to maintain our superiority while saving money and saving lives.

In both Iraq and Afghanistan, solar and energy-efficient technologies enabled soldiers and Marines to carry less gear and make fewer dangerous re-supply missions. Across the services, reducing the number of fuel vehicles and convoys means a more mobile, efficient and therefore lethal and effective force.

It also means fewer American troops and civilians, driving or guarding those convoys, are vulnerable to attack.

The latest salvo in the fight over Navy investments in alternative fuels is a Reuters article citing a newly released report by the Rand Corp. As the article puts it, the report finds that “renewable fuels for U.S. military ships and jets are likely to remain ‘far more expensive’ than petroleum products absent a technological breakthrough.”

This is hardly news. Mabus has acknowledged that alternative fuels are not yet price-competitive with fossil fuels. Technological breakthroughs are what further research and development must accomplish.

As Mike Breen, vice president of the Truman National Security Project, pointed out, if we hadn’t allowed the Navy to invest in anything more sophisticated than a compass, we wouldn’t have GPS.

Other studies report that price competitiveness may not be so distant. The most recent Rand report even cites a 2011 Rand study that asserts that “developing a competitive alternative fuel industry in the United States offers important benefits to the nation.”

And this is exactly what Navy investments in alternative fuels would do — help boost the fledgling industry, with long-term, strategic benefits to the country.

Mainers should hope that Maine’s congressional delegates will work to ensure that the House and Senate measures are defeated. Mabus’ energy priorities, and those of our military leadership more broadly, make sense — common sense, moral sense and strategic sense.

Kate Bateman, a Truman National Security fellow and an Army wife, has worked in the Defense and State departments in Washington, Afghanistan and Sri Lanka. She is from Cumberland, and was a legislative assistant to U.S. Rep. Tom Allen from 2002-05.