The last time Mike Huckabee ran for president, the world of campaign finance was much more straightforward. Which may explain why, during the announcement of his 2016 candidacy on Tuesday, Huckabee stepped over one of the few clear legal boundaries that now exist in the world of money in politics

"I will be funded and fueled not by the billionaires, but by working people who will find out that $15- and $25-a-month contributions can take us from Hope to higher ground," he said, making his announcement in Hope, Ark. And then he added, to laughter, "Now, rest assured, if you want to give a million dollars, please do it." It was mostly a joke. It also violated campaign finance law.

"A federal candidate cannot solicit a million dollars, let's start there," said Larry Noble of the Campaign Legal Center when The Post reached him by telephone. "If he's there announcing his candidacy, he cannot ask anybody for a million dollars. The most he can ask is the contribution limit; from a PAC that's $5,000."

Huckabee's campaign, of course, can't take a million-dollar contribution, suggesting that his comment was pointing people to give to a super PAC. Huckabee can ask people to give to the PAC, but only up to the limits stated above.

What's more, that PAC has to be independent of Huckabee's campaign. "To the extent that he's implying that the money is given to him or will help him, that undermines the concept of independence," Noble said. Huckabee didn't say to give him the money, which would suggest a coordination that could violate the law. But he'd certainly be happy to have people give to Pursuing America's Greatness, the PAC formed to bolster his candidacy.

"It's what everyone knows — that giving money to the super PAC is the same as giving the money to him," Noble added. "The legal fiction is saying, oh, you're not giving me the money. But in this unguarded moment, he actually spoke what the truth is." Any candidate is happy to have millions of dollars flow into PACs that are supporting them.

Huckabee was making a joke, as he does. But the law on this is clear, and while boundaries between PACs and campaigns are eroding, the boundary against candidates making requests for a million dollars is clear.

As Noble put it: "Words matter."