Rep. Debbie Dingell (D-Mich.) mocked Donald Trump on Tuesday by suggesting he rename Lake Ontario after his devoted aide, Natalie Harp, after Trump suggested renaming the body of water amid his ongoing trade war with Canada.

In a social media post, Trump threatened to rename Lake Ontario to “Lake America.”

“The United States is giving serious consideration to changing the name of Lake Ontario to Lake America in that we don’t expect to doing much business with Ontario any longer. Thank you for your attention to this matter!” he wrote on Truth Social.

Dingell fired back in a post on Twitter, writing, “Let’s just call it Lake Natalie so we know you’ll start protecting our Great Lakes.”

‘Natalie’ is in reference to Trump’s executive assistant, Natalie Harp, whose extraordinarily close relationship wth Trump has come under scrutiny after Georgia Sen. Jon Ossoff (D) told supporters at a rally earlier this month that Trump only “wants to build his ballroom and travel with Natalie in their apparently defenseless flying palace gifted by the Emir of Qatar.”

A deeper dive into Harp and Trump’s relationship revealed that she had written several letters to Trump expressing her utmost devotion and loyalty to him.

In the letters, obtained by The Daily Beast, Harp called Trump her “guardian and protector” and said she is “unworthy” of him. Photos also show Harp chasing Trump’s golf cart. CNN reported that Harp once rode in the trunk of an SUV to be close to Trump.

Harp’s displays of devotion to Trump concerned some White House staff and alarmed the Secret Service.

In a statement, White House spokesman Davis Ingle said that Harp “is one of the most loyal and hardest-working aides on President Trump’s team.”