Sen. Ron Wyden (D-OR) reintroduced a bill Thursday that would force sitting presidents to release their tax returns publicly.

Wyden first proposed the measure after Trump became the all-but-assured Republican nominee in May 2016.

The bill would require both sitting presidents and presidential nominees to disclose their tax returns. Wyden’s reintroduction of the bill follows on a House proposal to require presidential nominees to disclose the past 10 years of their tax returns.

At the same time, the battle over Trump’s tax returns is set to heat up. Rep. Richard Neal (D-MA), the incoming chair of the Ways and Means Committee, is the only Democrat in Congress with the authority to request Trump’s returns from the Treasury Department, a move he is expected to take, though the timing remains unclear.

That request will likely be turned down by Treasury Secretary Steve Mnuchin, setting the stage for a protracted legal battle.

In a statement, Wyden referred to his Senate bill as a move that would “ensure public transparency if Trump’s tax returns get tied up in court.”