Democrat Elijah Cummings chairs the House Oversight Committee, a tough job made tougher by White House stonewalling and by Republicans on the committee trying to torpedo an investigation into prescription drug pricing. Ranking member Jim Jordan of Ohio and his GOP sidekick Mark Meadows sent letters earlier this month to the CEOs of 12 pharmaceutical companies advising them not to cooperate with Cummings’ requests for information, alleging that the chairman would leak the information and tank stock prices.

Jordan and Meadows are the Thelma and Louise of the GOP, driving the party over the cliff. They’ve tried to protect Donald Trump from his former fixer Michael Cohen’s damaging testimony, calling Cohen a liar and echoing White House calls to investigate Hillary Clinton and the origins of the Russia probe. But shielding Big Pharma is another matter. It does not play well with voters, even some Republican ones—something Trump understands, at least rhetorically. He said in his first press conference as president-elect that the drug companies “are getting away with murder,” a charge he periodically repeats to bolster his populist credentials.

He even followed up with a proposal to allow Medicare to negotiate lower prices with pharmaceutical companies, which it currently cannot do, thanks to the enormous sums of money spent by the drug lobby to protect their profits.

Cummings wants to know why the cost of insulin for diabetics has skyrocketed, and the price of drugs to treat multiple sclerosis are rising much faster than inflation. Drug companies spend twice as much money on marketing as on research, while claiming higher prices are essential to bring new lifesaving drugs to the public.

News stories about people having to ration medication because of the cost, or go without and risk death, are shaming the industry and beginning to penetrate the iron curtain of secrecy around drug pricing.

At any other time perhaps those 12 drug companies would have heeded the Thelma and Louise calls to boycott the oversight committee. But not this time. A senior Democratic committee aide tells The Daily Beast, “All 12 companies committed to complying with the committee’s requests in January, and they have been producing information on a rolling basis, although some are further along than others. After Rep. Jordan sent his letters urging the drug companies not to comply, several expressed surprise and concern, but no company said it would refuse to cooperate, and we continue to expect full compliance going forward.”

The argument that Jordan and Meadows made to the drug companies about how data obtained by the committee would be leaked to embarrass them and potentially sink their stocks is based on their interpretation of how Cummings handled White House whistleblower Tricia Newbold. She testified last month behind closed doors about her concerns that the White House was not following proper procedures in issuing security clearances.

Republicans claimed then that Cummings released sensitive information from that session. Cummings denied these claims, which appear to be unfounded. Yes, he released “cherry-picked excerpts” but no, he didn’t violate national security. “Your efforts to interfere with this investigation represent a new low for a member of this Committee,” Cummings said in his written rebuke to Jordan, the ranking Republican.

Partisan warfare is not uncommon on committees, but no one can recall one party acting so blatantly to undermine a legitimate committee investigation which serves the interests, at least rhetorically, of both parties, and of the American people. “It is one thing to have an honest disagreement about the committee’s policy or approach—which would command respect—but it is quite another to actively obstruct an investigation in the service of placing corporate interests over those of the American people,” Cummings wrote.

Politicians in both parties rely on campaign contributions from drug companies. Otherwise the prohibition on Medicare bargaining for lower prices would have been lifted long ago.

If President Trump can achieve a victory on Medicare pricing that eluded President Obama, it would be the first time the powerful pharmaceutical industry took a hit. And it would signal an important change in Congress, that there is for the first time majority agreement that something needs to be done to restrain the cost of prescription drugs.

Cummings met with Trump in the White House a year ago to talk about curbing drug prices, after which Trump claimed Cummings told him he will go down as one of the great presidents in the history of the country. Not quite, Cummings said in a statement explaining that he predicated his prediction on Trump taking steps “to truly represent all Americans rather than continuing on the divisive and harmful path he is currently on.”

This week, Trump sued Cummings in an attempt to quash a subpoena issued by the Oversight committee to Mazars USA, the accounting firm that Trump has used since the early 1980s to prepare annual financial statements that Michael Cohen said in sworn testimony were falsified to make Trump seem richer than he is, and to secure loans under false pretenses.

The suit, filed in federal district court, is seen by legal experts across the political spectrum as a long shot effort to overturn decades of legal rulings by asserting that Congress can’t probe the executive’s financial dealings unless there is a legislative component. Trump’s attorneys cite an 1880 law as precedent, but that law was overturned in 1927. Congress’ right to investigate has been viewed broadly by the courts. The long-running Whitewater investigation of President Clinton was based on a land deal in Arkansas that pre-dated his presidency.

Cummings said in a statement, “The President has a long history of trying to use baseless lawsuits to attack his adversaries, but there is simply no valid legal basis to interfere with this duly authorized subpoena from Congress.”

There may not be a valid legal basis, but the wheels of justice move slowly, and the goal may be to delay and delay, tactics that stymie the opposition as documents are withheld, executive privilege is claimed, and the clock ticks down to November 2020 .