Former Democratic Sen. Harry Reid said Wednesday a comment he made decades ago about birthright citizenship was a "mistake."

Following the re-emergence of a video clip from 1993 in which he lamented how U.S. immigration policy “rewards” people who enter the country illegally by giving citizenship to their children, the one-time Senate majority leader explained his change of heart.

“After I proposed that awful bill, my wife immediately sat me down and said ‘Harry, what are you doing? Don’t you know that my father was an immigrant,” Reid said in a statement. “In my 36 years in Washington, there is no more valuable lesson I learned that the strength and power of immigrants and no issue I worked harder on than fixing our immigration system.”

The statement came after President Trump and his allies shared the video clip of Reid, quipping that they agree with his stance.

“Harry Reid was right in 1993, before he and the Democrats went insane and started with the Open Borders,” Trump tweeted Wednesday. The president later posted a video of Reid’s speech to his Twitter account.

Trump revealed this week that he is planning to end birthright citizenship via executive order, which was met with sharp criticism from Democrats, while constitutional scholars and House Speaker Paul Ryan, R-Wis., have expressed doubt that such a move is legal.

“You cannot end birthright citizenship with an executive order,” Ryan said.

“Paul Ryan should be focusing on holding the Majority rather than giving his opinions on Birthright Citizenship, something he knows nothing about,” Trump said in a separate tweet about the speaker. “Our new Republican Majority will work on this, Closing the Immigration Loopholes and Securing our Border!”

Meanwhile, Sen. Lindsey Graham, R-S.C., has said he will offer legislation to end birthright citizenship.