President Donald Trump's fall push for the Republican tax-reform effort kicks off Wednesday in Springfield, Missouri. And according to Ben White and Tara Palmeri at Politico, Trump's message will paint the tax policy as a populist change aimed at "unrigging the economy."

The Trump administration has said for months that it will aim to bring down taxes for all while closing loopholes, but Trump's speech is expected to have a decidedly populist tone.

The speech, crafted by Trump aide Stephen Miller, will feature phrases like "win again" and promises to "jump-start" the American economy, Politico reported.

The speech will reportedly be light on policy details. That seems to be, in part, because there are few concrete details to present at this point.

White House officials, including Gary Cohn, the National Economic Council director, have said the administration is looking to the congressional committees in charge of taxes to hammer out a plan.

"In the next three or four weeks the tax bill will be written in the Ways and Means Committee and Congress is going to own the writing of legislation — that is key," Cohn told the Financial Times on Thursday.

So while there have appeared to be some broad agreements between Trump administration and congressional leaders, what ends up in legislation remains unclear.

Opening the process to more than just the so-called big six — Cohn, Treasury Secretary Steven Mnuchin, Senate Majority Leader Mitch McConnell, House Speaker Paul Ryan, House Ways and Means Committee Chair Kevin Brady, and Senate Finance Committee Chair Orrin Hatch — also opens the negotiations to industries interested in protecting favorable deductions and the concerns of rank-and-file members.

According to Bloomberg's Sahil Kapur, major planks of the tax plan have not been nailed down.

While selling the unfinished tax plan appears to be the next big push from Trump and the White House, it is far from the top of the list for Congress' to-do list next month.

Not only will the legislature have to deal with the relief efforts for Hurricane Harvey, but it must also deal with the debt ceiling, avoiding a government shutdown, and a slew of agency reauthorizations before the end of September.

Most experts doubt that Trump's aggressive timeline seeking to pass a tax plan this year is feasible.

"There will likely be months of committee hearings, lobbying by affected groups, and behind-the-scenes horse trading before final tax legislation emerges," JPMorgan economists Michael Feroli, Jay Barry, and Jesse Edgerton wrote in a note to clients on Tuesday.

"Our baseline forecast continues to pencil in a modest, temporary, deficit-financed tax cut to be passed in 2Q2018 through the reconciliation process, avoiding the need to attract 60 votes in the Senate."