Those supporting the amendment, which passed on a 62-37 vote, said it would save lives and money.
“Our military is on the cutting edge technologically, but much of our fighting capability relies on foreign fossil fuels and decades-old power systems. That dependence has very real human and economic costs. Today’s strong bipartisan vote affirms that we should allow our military leaders to continue to develop and use advanced alternative fuels in order to bring down costs and improve mission capabilities," Udall said in a Wednesday statement.
Inhofe argued that biofuels are too expensive, with $500 billion of defense cuts slated for the next 10 years as part of sequestration.
Inhofe, along with other Republicans, opposes using military spending to commercialize energy technology, though several senators argued the Defense Department has a history of investing in less mature energy sectors.
Still, Inhofe said biofuels are something the Department of Energy should be spending money on, not the Department of Defense.
“This is something [the Department of Energy] should be doing if anybody is going to be doing it,” Inhofe said on the floor Wednesday. “This one amendment, more than any other, would take money away from readiness.”
But the amendment's Senate proponents said biofuels could help keep military energy spending down by reducing the military's exposure to oil price shocks.
The program has the support of Defense Secretary Leon Panetta and Navy Secretary Ray Mabus, who also contend it would stabilize energy costs. They call the program vital for energy security, saying it gives the military more fuel options and loosens it from foreign oil’s grip.
Sen. Barbara BoxerBarbara BoxerFeds weigh whether carbon pollution should be measured in highway performance Juan Williams: Dems should not take Latinos for granted Reid faces Sanders supporters' fury at DNC MORE (D-Calif.) asked if the Senate has to once again have a fight about oil.
“Is big oil calling the shots here?” Boxer said Wednesday before the vote. “I would hope not, but I don’t understand why this section Sen. Udall is trying to strike is in this bill when the military says it’s critical to them.”
Republican senators voting with Democrats to approve the amendment included Sens. Roy BluntRoy BluntTrump, Clinton running even in Missouri Top Republican presses Kerry for Iran 'ransom' details AFL-CIO urges GOP senators to 'renounce' Trump MORE (Mo.), Thad CochranThad CochranWhy a bill about catfish will show whether Ryan's serious about regulatory reform Capitol locked down for second time in a week This week: Congress eyes the exits in dash to recess MORE (Miss.), Susan CollinsSusan CollinsGOP senator considering Libertarian ticket Trump’s Second Amendment people threaten Hillary’s legacy, not life Sunday shows preview: Trump's tough week MORE (Maine), Chuck GrassleyChuck GrassleyThe Trail 2016: Trump works to widen his appeal Dem challenger launches first TV ads in race to unseat Grassley Dem wants hearing on EpiPen price hikes MORE (Iowa), John HoevenJohn HoevenMajority of GOP senators to attend Trump convention Death threats against senators remained on Twitter for 2 weeks Senate panel approves funding boost for TSA MORE (N.D.), Dick Lugar (Ind.), Lisa MurkowskiLisa MurkowskiMcAuliffe: I wouldn't want a 'caretaker' in Kaine's Senate seat Big Oil makes a push for risky and reckless Arctic drilling GOP divided over 0M for climate fund MORE (Alaska), Olympia Snowe (Maine) and John ThuneJohn ThuneApple, Google enlisted for FCC robocall effort Fidelity denies lobbying for student loan tax break Republicans see fresh chance to overhaul telecom law MORE (S.D.). Democratic Sens. Joe ManchinJoe ManchinGiffords-backed gun control group endorses Toomey, Kirk Sandy Hook relative backs GOP Sen. Toomey Christian voters left wanting in Trump vs Clinton MORE (W.Va.) and Jim Webb (Va.) voted against the amendment.
Collins, who serves on the Armed Services Committee, missed the May committee vote on the Inhofe amendment, which passed by one vote.
The Truman National Security Project's Operation Free campaign, which aims to wean the U.S. off oil, praised the Senate for passing the amendment.
"Our dependence on oil as a single source of transportation fuel endangers our national and economic security. We spend billions of dollars every year securing strategic chokepoints in the global oil supply line, and any rise in oil prices leaves the DoD on the hook for millions or even billions in additional fuel costs," Mike Breen, executive director of the Truman National Security Project, said in a Wednesday statement.
Biofuels groups said the vote showed the nation is committed to alternative fuels.
"Reports of the demise of biofuels political currency appear to be premature. Americans clearly support reducing our dependence upon foreign oil and strengthening our national and economic security via domestic renewable fuels," Renewable Fuels Association CEO Bob Dinneen said in a Wednesday statement.
— This story was last updated at 11:59 a.m. Thursday.