He said he would change the United States constitution's 14th amendment, which gives citizenship to all born on U.S. soil, via an executive order.
"This has not been a serious debate other than in academic circles", said Napolitano.
We'll have more on Trump's attempts to circumvent the 14th Amendment's birthright citizenship clause after headlines with historian and author Martha Jones.
According to Axios, Mr. Trump said that he has run the idea of ending birthright citizenship by his counsel and plans to proceed with the highly-controversial move, which certainly will face legal challenges.
"If he can do DACA, we can do this by executive order", Trump said, using the acronym for the Obama-era Deferred Action for Childhood Arrivals program.
The practice extends citizenship to children born in the United States, even if their parents are unauthorized immigrants.
The U.S.is not the only country to grant birthright citizenship, with Canada and a number of Latin American countries also doing so, but the issue has always been a contentious one in the U.S. - particularly for those seeking to restrict illegal immigration into the U.S.
President Donald Trump's decision to bring an executive order to end the right to the USA citizenship for children born in the U.S.to non-citizens has invited widespread criticism, even from his own party.
Here's a sampling of how the USA compares to other nations on citizenship requirements.
Amending the constitution involves the cooperation of either two-thirds of Congress or three-fourths of all states, neither is likely for changing birthright citizenship given the current political climate.
"Finally, a president willing to take on this absurd policy of birthright citizenship". Six of the Justices ruled that the phrase "and subject to the jurisdiction thereof" applied to any person required to obey USA laws, meaning even children of foreigners residing in the country permanently or temporarily.
On Wednesday, Trump appeared to shift stance somewhat by avoiding saying it would be ended by executive order, while acknowledging the matter "will be settled by the United States Supreme Court". The 14th Amendment's citizenship guarantee is clear.
He also took aim at former Senate Democratic Leader Harry Reid, who he said "was right in 1993, before he and the Democrats went insane and started with the Open Borders (which brings massive crime) 'stuff'".
The Supreme Court has not ruled specifically on the issue of whether illegal immigrants can be denied birthright citizenship.
"We're a nation of immigrants so if I were to bet I would think the president is going to lose", he said.