The race to succeed Prime Minister Theresa May is becoming a battle over whether Britain should leave the European Union without a divorce agreement — or whether that would cause economic and political mayhem.

May's Conservatives are reeling after the upstart Brexit Party won Britain's election for European Parliament seats. The Conservatives came a humiliating fifth.

That led some Conservatives, including leadership contenders Boris Johnson and Dominic Raab, to argue that the U.K. must leave the EU as scheduled on Oct. 31, even if it hasn't approved a withdrawal deal.

Others say crashing out of the bloc would be reckless.

Foreign Secretary Jeremy Hunt said Tuesday that trying to leave without a deal would lead Parliament to trigger a national election that would be "absolutely catastrophic" for the Conservatives.