The quick-tempered seventh president of the United States may lose his spot on the $20 bill if a group of seven Democratic senators get their way. In a letter sent to President Barack Obama on Thursday, the lawmakers urged him to convene a Treasury panel that could change the likeness on the bill. Front-runner to replace Jackson? Harriet Tubman.

“We recognize that it is fully within the Administration’s powers to convene [a Treasury panel to change the bill] and we encourage you to do so as soon as possible,” the letter read. The signatories were Sens. Jeanne Shaheen (N.H.), Dianne Feinstein (Calif.), Mazie Hirono (Hawaii), Kirsten Gillibrand (N.Y.), Angus King (Maine), Sheldon Whitehouse (R.I.), Tammy Baldwin (Wis.) and Dick Durbin (Ill.).

The letter follows growing grassroots support to put a woman on American currency. Women On 20s, a group referred to in the letter to Obama, held an informal vote to determine which woman to push for and has a petition for supporters to sign to urge the action.

The movement even got a response of sorts from the president in April. A 9-year-old girl from Massachusetts wrote a letter to the president asking him why women weren’t on U.S. currency and offered a few names she felt were worthy of the honor. Among those names were Anne Hutchinson, Rosa Parks, Betsy Ross and Tubman.

Obama later said it was a good idea in a speech, and then wrote to the 9-year-old. “This is a belated note to thank you for writing to me with such a good idea last summer,” he wrote. “The women you listed and drew make up such an impressive group, and I must say you’re pretty impressive too.”

The folks who started the Women on 20s petition in March had two main reasons for choosing Jackson as the president most worthy of being bumped from the bills. The first is his signature on the Indian Removal Act of 1830, which drove Native Americans from their homes on the Trail of Tears. The second is that Jackson wasn’t too excited about the central banking system; he preferred gold and silver as a currency. Not dollar bills.

The Women on 20s organizers, according to Financial Times, ramped up their engagement with the mission when Obama mentioned the idea in that speech. Over a 10-week period that ended in May, the Women on 20s poll garnered 600,000 votes.

There have been women on American currency before, though. The first was Susan B. Anthony, who was put on a dollar coin during the Carter administration. Sacagawea is still on one today holding her infant son Jean Baptiste.

The $20 bill has had a few other people on it other than Jackson, even a woman. Abraham Lincoln, now on the five dollar bill, was once on the bill; as was Alexander Hamilton; two-time secretary of the Treasury Hugh McCullough; James Garfield; Supreme Court Justice John Marshall; George Washington; Commodore Stephen Decatur; Secretary of the Treasury Daniel Manning; and Grover Cleveland. The woman? Lady Liberty, most recently in the 1880s.