A president lets fly on Twitter early on a Saturday morning with accusations that his predecessor had him wiretapped, and just like that this country is off on an another wearying, surreal, destructive distraction.

First, let’s state that President Trump’s assertion, that President Obama had Trump Tower wiretapped in the waning months of the 2016 election, came without evidence. But it did perform one important public service: It emphasized the need for Congress to appoint — without delay — an independent prosecutor who is empowered to investigate Russian interference in the election and that country’s ties to the Trump campaign.

The questions about the Trump campaign’s Russian ties arose early in the election and have continued to dog the Trump administration in the six weeks since he took office. It is the thread that runs throughout this mess, whether it’s Jeff Sessions’ undisclosed meetings with the Russian ambassador; former campaign foreign-policy adviser Carter Page’s connections to that country; Trump’s own call that Russia hack rival then-rival Hillary Clinton, or the contradictory statements about the Trump empire’s dealings with that country.

At every opportunity, Trump’s response has been to throw mud instead of light. He easily could have released his tax returns to show whether he had business dealings with Russia, but he refused. If he had concerns about a wiretap, he has only to get the original wiretap request declassified. Trump — or his advisers — know full well that a president cannot order a wiretapping, that the FBI must have a federal lawyer who presents evidence of probable cause to a judge, who then authorizes the warrant. There is no need to speculate about a wiretap, let alone to say, without any substantiation, that one has occurred.

Either way, Trump may find this is one tweet that backfires. Evidence of a legal wiretap would mean a federal judge found probable cause to merit surveillance on campaign ties to Russia. If no evidence of a wiretap is found, it means Trump perpetrated a monumental falsehood with no foundation. Both outcomes are bad.

It is clear that Sessions — who recused himself from any campaign investigation only under extreme pressure — won’t dare cross his boss. His Justice Department has not even seen fit to comment on the assertion that a former president ordered surveillance on a political opponent in the last weeks of an election. On the other hand, FBI Director James Comey — who was reappointed by Trump — wasted no time in calling the claim false. Former Director of National Intelligence James Clapper also has denied “absolutely” that a wiretap was ordered for Trump Tower.

This country can ill afford to have some of its most important law enforcement entities at war with one another and with the administration. Sadly, Congress’ extreme reticence to take on the fomented ravings of this president means it is no longer in a position to do a credible investigation. Americans deserve — and want — answers on whether an adversarial nation had inappropriate ties to a presidential campaign. A recent CNN/ORC poll shows that two-thirds of the public supports the appointment of an independent prosecutor who can put these issues to rest. It is the same poll that shows more than half still supporting Trump.

Answers are needed soon, because there are real and important national security issues that must be attended to. Not the least of these is North Korea’s launch of four ballistic missiles on Monday within 200 miles of Japan’s northwestern coast. Instead, energy has been diverted to the verbal grenades thrown by a man who seems to struggle with focusing on the very demanding job he so badly wanted.

Congress must appoint an independent prosecutor who can go where the investigation leads on Russian involvement. We call on the Minnesota delegation, particularly Republican members Tom Emmer and Jason Lewis — a newcomer who promised during the election to be an independent voice — to publicly support such an appointment. This is not about disloyalty to a president, but loyalty to those who had faith that their representatives would act in the best interests of this nation.