In his speech to Congress Tuesday night, President Trump mentioned that he wants to make child care "accessible and affordable," but didn't offer details.

One idea he's likely considering, however, would be unlikely to accomplish that goal, experts say. Yes, it would offer some help in paying for childcare -- but most of it would go to people who are already quite wealthy.

The plan, being floated by Ivanka Trump on Capitol Hill in recent weeks, would make child care expenses tax-deductible for individuals earning up to $250,000 and for couples earning up to $500,000. Parents could deduct no more than the average cost of child care in their state. They also potentially could create a dependent-care savings account, which would be similar to a health savings account, and would top out at $2,000 a year. A refundable rebate, which could be worth up to $1,200, would be available for those who don't have any tax due.

That plan is estimated to cost $500 billion over 10 years.

"It's really very skewed toward higher-income families, which is the biggest problem with it," says Angela Rachidi, a research fellow in poverty studies at the American Enterprise Institute. "It's very expensive, and it isn't targeted to the right people."

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Women entrepreneurs are especially affected by the lack of affordable, high-quality, and accessible care for their kids. "It's pretty clear that caring for children is a barrier for women entrepreneurs," says Jason Wiens, policy director for the Kauffman Foundation, citing a study that looked at men and women who had a PhD in a scientific field. The women were significantly less likely to become entrepreneurs if they had a child under the age of two. For men, having a young child made no difference to their likelihood of starting a business.

To anyone paying for child care, any help is welcome. The average cost of child care is slightly under $10,000 per year per child, says Brigid Schulte, director of the Better Life Lab for New America, a nonpartisan think tank. According to a recent study from New America, child care in 33 states is more expensive than in-state tuition at a state university.

The Trump plan "would help some, so I don't want to dismiss it, but it's a drop in the bucket when you consider what's needed," Schulte says. "A much better way to go would be to have a robust investment in building a high-quality, affordable, accessible system." She suggests looking to the U.S. military, which provides care for 200,000 children, as an example of a system that works well.

Rachidi says using the tax system to get child care assistance to middle-income families makes sense, in part because it doesn't require any additional administrative infrastructure. It's a little harder to use the tax system to help low-income families, she adds, partly because the benefit is paid out once a year, as a lump sum.

Still, the price tag is likely to be the Trump plan's biggest stumbling block, especially because a good chunk of the money would go to parents who are not exactly cash-strapped. "You have to ask, what do you want to use public funds for?" says Rachidi. "Do you want government money to go to people who make above-average incomes?" Or, as Schulte puts it, "You wonder how misguided it is that you can make $500,000 as a couple, and still deduct child care expenses."