evidence: The new Withdrawal Agreement replaced the controversial Irish backstop provision with a protocol. According to the revised deal, the entire U.K. left the EU customs union upon Brexit, but Northern Ireland continued following EU regulations and value-added tax (VAT) laws for goods, while the U.K. government collected the VAT on behalf of the EU. [...] The backstop emerged as the main reason for the Brexit impasse. It was a guarantee that there was no "hard border" between Northern Ireland and Ireland. It was an insurance policy that kept Britain in the EU customs union with Northern Ireland following EU single-market rules. The backstop, which was meant to be temporary and was superseded by a subsequent agreement, could only be removed if both Britain and the EU gave their consent.