President Barack Obama blasted Republican presidential front-runner Donald Trump on Monday for his "half-baked notion" to force Mexico to pay for a border wall by blocking immigrants from sending money back to their families.

In a memo to The Washington Post on Tuesday, Trump explained that it would be an "easy decision for Mexico" to make a one-time payment of $5-10 billion for the wall that he's promised to voters because cutting off remittances would decimate the Mexican economy.

Obama begrudgingly responding to the proposal at a press conference on Tuesday afternoon.

"I am getting questions constantly from foreign leaders about some of the wackier suggestions that are being made," the president admitted. "It's not just Mr. Trump's proposals. You are also hearing concerns about Mr. Cruz's proposals, which in some ways are just as draconian when it comes to immigration for example."

"The implications with respect to ending remittances, many of which by the way are from legal immigrants and from individuals who are sending money back to their families are enormous," he pointed out. "First of all, they're impractical."

"The notion that we're going to track every Western Union bit of money that's being sent to Mexico, you know, good luck with that. Then we've got the implications for the Mexican economy, which in turn, if it's collapsing actually sends more immigrants north because they can't find jobs back in Mexico."

Obama called the proposal "just one more example of something that is not thought through and is primarily put forward for political consumption."