The long-awaited (albeit nervously) US Presidential campaign gets underway in earnest today, with the Iowa caucuses, the first step in a winnowing process that formally ends in the US Virgin Islands on 8 June. It’s only the Republicans who are taking part this week, as the Iowa Democratic primary takes place on “Super Tuesday”, 5 March. There are 40 delegates up for grabs (out of 2,467 available overall) but it isn’t winner takes all – delegates are allocated according to the share of the vote achieved. So, what are we watching out for?

The opinion polling that has taken place in Iowa has shown Donald Trump polling steadily well ahead, with a strengthening of his position in recent months. FiveThirtyEight suggests that his average poll score is over 50%, with many individual polls showing him doing even better. But Iowa is a socially conservative state with a strong evangelical influence, where Trump lost to Ted Cruz in 2016 – will Iowa Republicans waver in the face of his legal problems? And, if they do, at what percentage does he begin to look vulnerable?

The real contest is for second place. For most of the campaign thus far, the likely runner-up was Ron DeSantis, but his support started to slip away during the summer, and the recent emergence from the pack of Nikki Haley leaves the two of them tightly bunched. Haley has the momentum, and with the South Carolina primary (where she has hometown advantage, as Governor from 2011 to 2017) due to take place on 24 February, coming second on Monday would draw out support that might be enough to give her an outside chance of beating Trump then.

There are two other candidates still on the ballot, Vivek Ramaswamy, whose goal appears to be to get a job in an incoming Trump administration but is now polling approximately 7%, and Asa Hutchinson, the former Governor of Arkansas, who appears to be focussed on suggesting that Donald Trump is unfit to be the Republican nominee, let alone President. Surprising though it may seem, in terms of this contest, he is utterly irrelevant.

There is one factor that is beyond the candidates, which is turnout. And turnout is likely to be affected by the weather on Monday, which is predicted to be brutal. Whose supporters are more likely to be deterred, will urban Republicans (potentially less likely to support Trump) have more influence in the result and, if they do, is Haley likely to benefit most? Here’s the Washington Post’s take on the influence of bad weather on turnout.

But you’d want me to stick my neck out and predict an outcome, wouldn’t you? So, here goes. I’m predicting that it’ll shake out like this:

• Trump – 54% (21 delegates)
• Haley – 22% (9 delegates)
• DeSantis – 18% (7 delegates)
• Ramaswamy – 6% (3 delegates)
• Hutchinson – >1% (no delegates)

We’ll see how close that is soon enough…

* Mark Valladares is a former member of the Party’s Federal International Relations Committee and volunteered at the 2000 Democratic National Convention.