Former New Jersey Gov. Chris Christie began his return to the national political stage with an opening message: 'Go big' – then flashed his ability to go for the jugular. He denied running for president as a spoiler but said he did want to take down Donald Trump – who he hit for 'coddling' Vladimir Putin, running 'failed casinos' and 'reprehensible' bartering of Ukrainian aide that was the subject of Trump's second impeachment. He said Americans knew Trump was 'full of it' when he said Mexico would pay for the border wall, then vowed not to make the mistake of...