In the US rich people are more republican than poor people.If you only factor in white people, rich white people are as republican as poor white people (it was in 2016 anyway). Middle class white people were the most republican. The key divide is education.
The breakdown I saw of the 2016 white vote had rich whites as the least pro-Trump (though Trump still won) and middle-income as the most with poor whites in between. However, the poorer a mostly white
area is, usually, the more pro-Trump - the exceptions being some poor white urban areas and of course college towns that are technically high-poverty. I think the fact that college students are often in the lower-income bracket skews the vote of "poor whites" to the left especially since they vote at higher rates than other lower-income groups.
Still there is an obvious difference from Canada where most poor white areas vote left, including poor white urban areas like East Vancouver and poor white rural areas like most of rural Quebec and Atlantic provinces.