It has long been clear that the only restraints on Donald Trump’s actions are the courts and the American people. Republicans have largely failed to act as a check on the US president, even when he is traducing the principles they claim to hold dear. One of these is the US constitution’s provision for a presidential election every four years.

A few Republican heads made rare appearances above the parapet recently after Mr Trump mused about delaying the November election. That was encouraging. He has no authority to postpone an event that has taken place without fail, including in the throes of the US civil war and two world wars. Yet they are willing accomplices in Mr Trump’s backdoor efforts to make it as hard as possible for Americans to exercise their right to vote. A suppressed turnout could prove as bad as a delayed election.

Of these, the most worrisome is Mr Trump’s assault on mail-in balloting, which he repeatedly describes without evidence as “fraudulent”. Amid a pandemic it is critical that voters be given an alternative to standing in long queues for crowded polling stations. Without a well-functioning US postal service, votes may not be cast, or arrive too late to be counted. Yet Louis DeJoy, the recently appointed postmaster general, who runs the USPS, is taking steps to make postal voting harder.