Story highlights Trump will unveil his tax plan during a speech Wednesday in Indianapolis

The President is also starting to weigh in with far more interest

Washington (CNN) President Donald Trump's highly anticipated tax plan, which he will unveil during a speech Wednesday in Indianapolis, will likely leave the door open to raising taxes on some of the wealthiest Americans, CNN has learned.

Two Republicans briefed on the still-evolving plan say the proposal will be intentionally shy on specifics when it is announced, for fear of alienating moderates and the conservative House Freedom Caucus.

"They don't want to give people enough details to oppose it," a Republican involved in the months-long process tells CNN.

The plan, which is expected to start selectively leaking out on Tuesday on Capitol Hill and to lobbyists across Washington, is still being carefully pored over by House, Senate and White House tax experts.

The President is also starting to weigh in with far more interest, one person involved in the process said, which could open the door to more last-minute changes.

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