Britain’s vote Thursday is set to be a textbook example of the limits of elections. When choices are clear, and articulated by strong leaders, elections can move politics forward. Otherwise, votes resolve nothing.

Six weeks ago, British Prime Minister Theresa May’s call for a snap election made sense. With her popularity high and her Labour Party opponents in disarray, she hoped to strengthen her position in Parliament, undercutting her party’s euroskeptic hard-liners and making it easier for her to negotiate the terms of Britain’s divorce from the European Union.

Since then, new terrorist atrocities have sidelined discussion about Brexit. May has waged a weak campaign and seen the once-commanding lead of her Conservative Party evaporate. A Labour win still looks unlikely, but anything less than a big Tory victory will leave May diminished, and the outlook for Brexit even more muddled.

Fact is, on the main issues – Britain’s exit from the EU and the persistent threat of Islamist terrorism – there isn’t much difference between the main parties. The Labour opposition isn’t promising to reverse Brexit, only to make it less disruptive. (It hasn’t said how.) Both parties have deplored the terrorist attacks with equal conviction and run up against the same trade-offs between security and civil liberties.

All of which has lent an air of near-irrelevance to Thursday’s vote. Issues of world-historical import bear down on British voters – and the election has had almost nothing to say about them.