Shaheen separately put a legislative bill in the hopper directing the Treasury secretary to put Tubman on the bill by 2017.  

Obama sounded positive in July about putting a woman on the currency.

"Last week, a young girl wrote to ask me why aren’t there any women on our currency, and then she gave me like a long list of possible women to put on our dollar bills and quarters and stuff — which I thought was a pretty good idea," Obama said then.

The White House of late has been asked about it a few times but offered no definitive answer. Treasury Secretary Jacob J. Lew, who has the authority to implement the change, ducked the question in March.

Here's the full letter from the senators:

Dear Mr. President:

As you know, a recent grassroots campaign has engaged hundreds of thousands of Americans behind a common mission: placing the likeness of a woman who has contributed to our nation’s history on our paper currency. Recently, the campaign concluded its online voting for potential candidates by choosing Harriet Tubman and has petitioned the White House to make this change. We write today to urge you to begin the process for selecting a woman whose likeness will be placed on the $20 bill.

Our paper currency is a ubiquitous part of our everyday lives. The images on these bills symbolize important American values and explain part of our identity as a nation. Yet, for more than 200 years, our paper currency has been reserved exclusively for men who have shaped our history. That’s why the time has come to honor the contributions that women have made to our society, and reaffirm that women will be an important part of our future.

Although our paper currency has been redesigned several times to improve legibility and prevent counterfeiting, the portraits on the seven main bill denominations have not changed in nearly a century. Those portraits were chosen by a special Department of the Treasury-appointed panel of citizens in the late 1920s. This year’s grassroots campaign has demonstrated that the time has come for a woman’s portrait to appear on the $20 bill.

We have introduced legislation, the Women on the Twenty Act, which would task the Treasury Secretary with appointing a new citizens panel to determine a woman whose likeness will be featured on a new $20 bill. Our legislation does not specify that any particular woman be chosen for this honor, but does request that the panel take into consideration the input of the American people.

We recognize that it is fully within the Administration’s powers to convene such a panel without Congressional direction and we encourage you to do so as soon as possible. Establishing this panel would get this process underway and allow for appropriate public input, including from the recent online polling results.

Thank you for your attention to this matter, and we look forward to working with you.

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