In an interview with Mike Allen for "Axios on HBO," Republican Sen. Mitt Romney said he opposes cutting the capital gains tax rate for the rich.

The big picture: Republicans typically argue that cutting the capital gains tax rate will boost economic growth and provide room for increased spending. Democrats argue that doing so disproportionately benefits the rich.

What they're saying:

"I believe in low tax rates. I also don't think that higher-income people should have a lower tax rate than lower-income people. I don't believe in continuing to cut capital gains tax rates, even though people say, 'Well, that'll encourage the growth of the economy.' It's like, 'Yeah, but it also puts more money in the wealthiest Americans, and that's simply not fair.'"

— Romney to "Axios on HBO"

Romney also said he is in favor of cutting the capital gains tax rate to zero for people who make under $100,000 a year.

Between the lines: President Trump has repeatedly tossed around the idea of a capital gains tax cut. But in September, he opted to not use executive authority to deliver the measure, according to the New York Times.