Badda Bing. Chris Christie has just endorsed Donald Trump for president, and suddenly Republican politics looks like a particularly nasty episode of the Sopranos.

As he paid homage to the new capo di tutti capi, Chris Christie called Trump 'the person who will do exactly what needs to be done to make America a leader around the world again'.

He talked about his 'long friendship' with Donald Trump, and said that Trump was 'the last person' Hillary and Bill Clinton wanted to face in the presidential election. The scene had a certain gangster atmosphere.

The endorsement might explain a few things. It explains why, to the surprise of many, Christie refused to go after Trump even as his candidacy failed. It also explains, perhaps, why the New Jersey Governor turned so viciously on Marco Rubio in the debate three days before the New Hampshire primary, damaging Rubio's candidacy at a vital moment.

Christie's reward might be the vice-presidency. A Trump-Christie ticket, with all the sleaze and nastiness surrounding the two men, would start to make the Republican Party look like it had been taken over by the mob.