Events which alter the dynamic
Last Thursday morning I was out on the campaign trail with Remain and Leave, and the difference in tone was striking.
Under the gaze of the statue of Nye Bevan, and surrounded by shoppers in the centre of Cardiff, Plaid Cymru welcomed the former SNP leader Alex Salmond at a relatively subdued event where Leanne Wood looked palpably worried about the prospects for the UK remaining in the European Union.
She said she'd been taken aback by the strength of feeling on immigration and called on people to think logically, rather than emotionally, on 23 June.
In stark contrast, I then went up the road to Caerphilly to a Leave event held under the gaze of the Tommy Cooper statue for an altogether noisier and more jovial affair.
There was a deafening microphone, huge Vote Leave posters and - never mind pedestrians - it seemed that traffic was being brought to a standstill.
Even the UK assembly member Nathan Gill admitted it had the whiff of a victory rally about it.
It was clear where the momentum stood. That was Thursday morning.
Soon after, news broke about the tragic death of Labour MP Jo Cox in Yorkshire and, as a result, campaigning was brought to a standstill virtually until Monday morning.
There is no doubt that a shocking event of that nature has altered the dynamic and momentum in the campaign.
We've had calls for the tone, particularly in relation to immigration, to be calmed down and all round it seemed to take the heat out of the contest while everyone had pause to reflect.
When things did get underway, Labour made a clear statement by sending two former Welsh Secretaries and a former and current First Minister out onto the streets of Pontypridd.
I'm tempted to use the old bus joke that you wait for months for a senior politician to campaign to remain in, and then four come along at the same time.
That's what it must have felt like for some as Lord Hain, Lord Murphy, Rhodri Morgan and Carwyn Jones did the rounds.
Most of the south Wales valleys are not used to close political contests as they are filled with so many safe Labour seats, but they are now at the centre of this battle as both sides believe there are more undecideds here than anywhere else.
If the Labour leadership is going to persuade its voters to remain, then somehow it has to allay their fears on immigration.
However, the Labour figures all said there had been a palpable shift in momentum during the weekend, partly because of the death of Jo Cox but also because they believe people start worrying about economic consequences as polling day approaches.
Of course, all sides claim to have the edge in the final stages, and Leave campaigners things they've picked up from where they left off.
But they know that allaying last minute jitters over the economy is a big challenge, or as Chris Grayling put it, when I asked him what he needed to do in the final week: "Stop people having second thoughts."
When I said to Nathan Gill that second thoughts can sometimes be a good thing, he agreed but was convinced that those people would stick with Leave, even having had the chance to stew over things for a few days when campaigning ground to a halt.
Let me take you back to Alex Salmond. He told me confidently he thought Wales would join the Celtic club by joining Northern Ireland and Scotland in supporting Remain.
I told him I wouldn't be so sure that would happen, and he responded by joking that it would if Wales started enjoying some serious success in the European championships.
Well one bit of that sentence is true. It remains to be seen if the other bit will as well.