WASHINGTON — One of the biggest lobbying clashes in recent years is heating up again: the fight to fund an alternate engine to power the Pentagon’s F-35 jet fighter.

More than a decade ago, engine maker Pratt & Whitney and its allies in Congress won out over General Electric Co. to be the exclusive supplier for the next-generation fighter. Now GE is once again lobbying Congress to provide billions of dollars to fund an alternative engine it would build, citing what it calls the flaws in Pratt’s engine. GE’s campaign is a challenge to fellow defense giant Raytheon Technologies Corp., which owns Pratt. Raytheon says developing a new engine could cost a total of $6 billion, a price tag that swells to $40 billion when calculated to include maintenance. Upgrading the Pratt engine would cost about $2.5 billion, according to the company.

The dispute is shaping up to be one of the biggest lobbying contests in Washington this year, when little aside from defense spending bills is expected to move through a bitterly divided Congress. It is also drawing criticism from groups that want to reel in government spending.

“No matter how wasteful, no bad idea is ever truly dead in Washington, especially when there are billions of dollars on the line,” said Steve Ellis, president of Taxpayers for Common Sense, a nonpartisan government watchdog. “You have to kill, kill, kill, until it’s dead, dead, dead.”