(CNN) -- Democrats are making presidential tax returns a focal point in one of their first pieces of legislation, an effort to build the case to the American people that time is up on President Donald Trump keeping his own tax returns from the public, shutting what could be a window into his personal wealth.

According to two sources familiar with the discussions, Democrats will include a provision in their new bill that would require presidential nominees to disclose 10 years of tax returns shortly after they become the nominee. Vice presidents would also be required to disclose a decade of returns. The tax returns would then be posted on the Federal Election Commission's website for public viewing.

The 10-year requirement is new marker. At the end of last year, Democrats had disclosed H.R. 1 would require presidential candidates to release just three years of tax returns, but a source familiar with the process said that after reviewing precedent, the marker was moved to a decade of returns.

The provision would be included in H.R. 1, a far-reaching bill that makes sweeping ethics changes as well as lays out Democratic priorities on voting rights and health care. The legislation isn't expected to pass the Republican-controlled Senate or be signed by Trump, also a Republican. However, it will give committees an opportunity to set markers on Democratic priorities in the new Congress.

The House Ways and Means Committee had planned to hold a hearing on the tax provision in H.R. 1 at the end of January. However, it could slip into February depending on the outcome of a partial government shutdown that has consumed Washington and left House Democrats spending their early days in the majority negotiating to reopen the government.

While Democrats take a legislative approach, they are fully aware that it isn't likely to be signed into law. The House Ways and Means Committee is also pursuing another route to obtain Trump's tax returns. Democrats believe under an obscure IRS rule, the incoming chairman of the House Ways and Means Committee, Rep. Richard Neal of Massachusetts, has the power to obtain the returns from the Treasury Department. Neal has said he plans to ask for them in the new Congress, but when exactly he'd make his move is still under discussion.

Trump has repeatedly refused to release his tax returns because he's under audit by the IRS. Being under IRS audit does not preclude someone from disclosing his or her tax returns.