Boris Johnson raises Brexit stakes with Irish border stance

The favorite to become Britain's next prime minister, Boris Johnson, has raised the Brexit stakes by saying he will discard a contentious part of the European Union divorce deal agreed by outgoing leader Theresa May

Britain's Parliament rejected May's deal, in large part because of a measure designed to ensure an open border between the U.K.'s Northern Ireland and EU member Ireland.

Brexit supporters think the so-called "backstop" keeps Britain too closely bound to EU trade rules. Some have argued for an exit clause or time limit.

But during a leadership debate Monday, Johnson rejected "time limits or unilateral escape hatches or all these elaborate devices."

EU leaders say there can be no withdrawal agreement without the backstop.