Will killing of MP change EU debate tone?
The killing of Jo Cox will never be explained away.
It's stopped politics in its tracks today, different party leaders putting their differences aside to show respect.
And the referendum campaign where respect has been scarce is still on hold.
Insults and exaggerations are never far from political exchanges.
But the referendum campaign has included astonishingly harsh attacks on both sides, emotional appeals to our identity that go way beyond the usual.
It is the biggest political decision we've been asked to make for decades, so it is not surprising that the campaign has been intense, but few in Westminster expected the debate over the EU to be so vicious.
But the MP's death hasn't just halted the contest, it's transformed the political mood in one moment.
And with the vote so soon, and the atmosphere so sombre, it's hard to imagine a full return to such confrontational campaigning before the country decides.
So when politicians are back on the trail next week, there's likely to be a kinder tone.
But in any campaign, pace and momentum matters. This pause could matter too.