About a month ago, the Alaska Dispatch News, the state’s largest newspaper, published a striking report on just how far Donald Trump’s White House was allegedly willing to go to lobby senators on health care. The ensuing controversy prompted an investigation, which apparently wrapped up this week.

To briefly recap, the Trump administration’s Interior secretary, Ryan Zinke, reportedly called both of Alaska’s Republican senators in July, explaining that Sen. Lisa Murkowski’s (R-Alaska) position on health care “had put Alaska’s future with the administration in jeopardy.” Murkowski’s colleague, Sen. Dan Sullivan (R-Alaska) went on the record at the time, saying the call from Zinke heralded a “troubling message.”

Sullivan added that the message from Trump’s cabinet secretary “was pretty clear.”

The prospect of the Trump administration threatening to penalize Alaska unless Murkowski went along with a regressive health care plan seemed plainly outrageous. The intimidation didn’t work – Alaska’s senior senator opposed the far-right health care gambit anyway – but reports of Zinke’s alleged tactics prompted the Interior Department’s inspector general to agree to take a closer look at what transpired.

At least, that was the idea. TPM reported yesterday on the outcome.

Unable to get either Alaska senator to spill the beans about allegations that a member of President Trump’s cabinet threatened funding to their state in order to secure their votes on a bill to repeal the Affordable Care Act, a government watchdog is closing his investigation into the matter. […] In a letter on Wednesday to the two House Democrats who demanded the probe … the Interior Department’s inspector general said that “further investigation would be unproductive.”

Deputy Inspector General Mary Kendall wrote, “Both Senators Murkowski and Sullivan declined to be interviewed or to provide statements regarding the matter. The OIG does not believe that it could meaningfully investigate the matter further.”

I suppose this isn’t too big of a surprise – we’re talking about two Republican senators from a red state, both of whom want to maintain good relations with a Republican administration – but it’s a shame. If Trump World threatened to hurt an entire state as some kind of ham-fisted attempt at political extortion, there should be an official examination.

We have hints about what happened, but if Murkowski and Sullivan won’t talk, we may never know the extent of the intimidation tactics.