The administration is under pressure to deliver. It wants to have a bill on President Trump’s desk by Thanksgiving.

So what happens between now and then?

Administration officials said that Mr. Trump would travel the country holding campaign-style rallies to promote a tax overhaul.

House and Senate tax-writing committees will begin marking up legislation shortly after Labor Day, according to Mark Short, the Trump administration’s legislative affairs director. Then, if the bills are passed in October and November, the tax legislation can get to Mr. Trump’s desk before December.

But there are still divisions on how the tax code would be revised:

The White House wants to cut the top corporate tax rate to 15 percent, from 35 percent.

House Republicans favor a cut to 20 percent, which several tax experts said was an ambitious goal. Even Orrin G. Hatch, the chairman of the Senate Finance Committee, thinks that getting to 25 percent would be a challenge.

And members of both parties are already objecting to the administration’s proposal to eliminate the deduction that Americans can take on their state and local taxes.