So when she received the letter in the mail, she pulled out her go-to purple pen and started making corrections. Then she snapped a picture, posted the letter on Facebook and mailed it back to the White House.

"It was a poorly worded missive," she said. "Poor writing is not something I abide. If someone is capable of doing better, then they should do better."

Mason, a Democrat who lives in Atlanta, had written to Trump to ask that he visit each family of those who died in the shooting that killed 17 people at a school in Parkland, Florida, in February.

"I had written to them in anger, to tell you the truth," she said. "I thought he owed it to these grieving families."

The letter she received did not address her concerns, she said. Instead, it listed a series of actions taken after the shooting, such as listening sessions, meetings with lawmakers and the STOP School Violence Act, a bill that would authorise $US500 million over 10 years for safety improvements at schools but had no provisions related to guns.

Then there were the grammatical errors.

"Nation" was capitalised, so was "states." Mason circled both.

A sentence about a "rule" banning devices that turn legal guns into illegal machine guns was unclear. "Explain 'rule,'" she wrote.

There was more. Much more.

"If my students turned that in they would get exactly the same marks," she said.

But she did not correct everything.

"I did not mention the dangling modifier," she said. "I focused mainly on mechanics."

The White House did not immediately respond to a request for comment.

The letter stood in contrast to other letters she has received from politicians, Mason said. Senator Lindsey Graham sent "beautiful" letters that struck a tone that "makes me more important than him," she said.