The US House of representatives has just voted to impeach Donald Trump, making him only the third US president to earn that dubiou distinction. But before anyone gets their hopes up, this isn't any return to constitutional normalcy. Once the House votes for impeachment, the Senate is supposed to conduct a trial. And the Republicans who dominate that body have shown no indication that they will do that properly, let alone vote to convict by the required two-thirds majority. So, the constitutional checks and balances fail because they ultimately rely on some measure of honesty and good faith from politicians. And where the US is concerned, that simply cannot be relied upon.
Meanwhile, its worth noting: Nixon - the man who provides the benchmark for a criminal US president - had enough decency and shame to resign before he got to this stage. Trump doesn't. Which is horrifying in a way.