General Motors and Nissan worry about losing money.

At least two major car companies set aside their differences to lobby against the proposed elimination of the federal government's electric vehicle tax credit.House Republicans recently suggested getting rid of the $7,500 credit before the end of the year as part of a wider tax reform designed to lower taxes for Americans and create jobs. Nissan and General Motors are among the companies going to great lengths to save the credit.

"Tax credits are an important customer benefit that can help accelerate the acceptance of electric vehicles. Because GM believes in an all-electric future, we will work with Congress to explore ways to maintain this incentive," the company wrote in a statement obtained by Automotive News.

Nissan released a similar statement, adding it has made "significant investments" in electric mobility. Both companies worry ending the tax credit will cause electric vehicle sales to slide, in part because they'll be considerably more expensive than comparable gasoline-powered models.

The lobbying efforts underline the importance of the federal tax credit in convincing buyers to give up gasoline. Saving the environment clearly comes at a cost many buyers are unwilling to digest without help from lawmakers.

It's not just about the Leaf (pictured) and the Bolt, either. Nissan and GM are both planning a sizable zero-emissions model offensive in the coming years which includes a Leaf-based crossover and a Buick-badged Bolt spin-off. Getting rid of the tax credit means these models (and dozens more) risk being stillborn because they'd fulfill a demand that no longer exists.

Automotive News adds lobbyists representing automakers are also attempting to convince the government to reinstate a similar tax credit awarded for the purchase of a hydrogen-powered vehicle. Nissan's zero-emissions offensive includes fuel cell vehicles, and GM has pledged to launch at least 20 electric and hydrogen cars by the year 2023.