"The law basically is a bullet aimed at New York and California," Clinton told CNBC in an exclusive interview on Tuesday, discussing changes to the tax code.

Former President Bill Clinton had some choice words about the new tax law.

The change means many residents in these states — and others — will now pay more to the federal government. (See chart below.)

For those who live in states with high income taxes , including California, Maryland, New Jersey and New York, that's a big hit.

The new tax legislation also doubles the standard deduction to nearly $12,000 for individuals and $24,000 for married couples who file jointly, which makes it much harder to claim the benefit for charitable contributions.

How this will affect people's willingness to give remains to be seen, Clinton said.

"They may be less inclined to contribute big money. I think people will still give," Clinton said. As a result, "we may have more crowdfunding."

"Depending on what happens with the elections, there may be some changes to that law," Clinton added, referring to the Tax Cuts and Jobs Act.

The tax cut bill, never broadly popular, has sagged in public esteem lately, an NBC News/Wall Street Journal poll in April found. Just 27 percent of Americans called it a good idea, down from 30 percent in January. A 36 percent plurality called it a bad idea, while the rest had no opinion.

Clinton took part in the 16th annual Commissions for Charity Day organized by trading firm BTIG on Tuesday, along with other politicians, all-star athletes, actors and journalists.

Since 2003, BTIG has raised more than $45 million for charity.

The former president's own Clinton Foundation operates a range of philanthropic projects around the world and has raised billions since its founding but has also been dogged by accusations of influence peddling and conflicts of interests.