Donald Trump Jr. and Paul Manafort have not personally confirmed that they will attend the hearing.
Three GOP senators already say they will not support an Obamacare repeal without an immediate replacement.
Trump takes a shot a Congress after the latest Republican plan to replace the Affordable Care Act collapsed.
President Donald Trump calls for a Senate rules change, but it would not have saved the Senate Obamacare replacement bill.
Jerry Moran and Mike Lee become the third and fourth GOP senators to say they would not support the Obamacare replacement plan as written.
President Trump urges Republicans to repeal Obamacare without a replacement after the latest replacement bill faltered.
The 80-year-old John McCain underwent surgery and President Donald Trump wants him back to vote on health care.
Support for Trump's impeachment is higher than Nixon's, though the pair had roughly the same approval rating at those points in time.
A delay on considering an Obamacare replacement bill after Sen. John McCain's surgery could be good for those opposing the plan.