Four weeks before the November 3 US midterm elections, Republicans trail Democrats by 9.6 points on the generic ballot in analyst Nate Silver’s midterm forecast model.

Democrats led by 9.1 points in my September 25 article. They remain clear favourites to gain control of the Senate and overwhelming favourites in the House of Representatives.

However, Donald Trump’s net approval has recovered from a low of -23.5 last Friday to -22.5.

If disruption caused by the Iran war continues until the midterm elections, with increased petrol prices and inflation, Republicans are likely to lose control of both the House and the Senate, perhaps with huge losses.

However, if the disruption eases again and petrol prices fall back before the midterms, I believe Republicans will do better than they are polling now, and may retain control of the Senate.

I say this because Trump’s net approval and the generic ballot were better for Republicans in early September, soon after a low in petrol prices.

In Silver’s aggregate of US national polls, Trump’s net approval is -22.5. Currently, 59.9% disapprove of his performance and 37.5% approve.

Trump’s net approval was -23.0 in my September 25 article. It had improved to -18.7 on September 4 before falling back.

Trump’s net approval is below what any past president since Harry Truman had at this point in their term, with Trump’s first term the closest at -10.5.

On four issues tracked by Silver, Trump’s net approval is -12.7 on immigration, -28.1 on trade, -32.8 on the economy and -48.5 on inflation. Since my September 25........

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