WASHINGTON — For more than a year, a rare coalition of liberal groups and libertarian-minded conservatives has joined the Obama administration in pushing for the most significant liberalization of America’s criminal justice laws since the beginning of the drug war. That effort has had perhaps no ally more important than Koch Industries, the conglomerate owned by a pair of brothers who are well-known conservative billionaires.

Now, as Congress works to turn those goals into legislation, that joint effort is facing its most significant test — over a House bill that Koch Industries says would make the criminal justice system fairer, but that the Justice Department says would make it significantly harder to prosecute corporate polluters, producers of tainted food and other white-collar criminals.

The tension among the unlikely allies emerged over the last week as the House Judiciary Committee, with bipartisan support, approved a package of bills intended to simplify the criminal code and reduce unnecessarily severe sentences.

One of those bills — which has been supported by Koch Industries, libertarians and business groups — would make wholesale changes to certain federal criminal laws, requiring prosecutors to prove that suspects “knew, or had reason to believe, the conduct was unlawful,” and did not simply unknowingly violate the law.