WASHINGTON -- President Trump was touting economic growth and job security Wednesday in St. Louis, but back at the White House jobs seemed anything but secure. Secretary of State Rex Tillerson was fired Tuesday, and there's talk of more change on the horizon.

CNBC television contributor Larry Kudlow was named director of the National Economic Council, replacing Gary Cohn, who announced his departure earlier this month.

"The greatest and most important thing for this and any other country that rapid economic growth and prosperity for everyone," Kudlow said. "That is my basic view and it has been for decades."

So far more than 20 senior administration staffers have either been fired, resigned, or reassigned.

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Secretary of Veterans Affairs David Shulkin, an Obama-era holdover, could be next to get the boot. In February, the department's inspector general determined Shulkin used taxpayer dollars on a lavish trip to Europe for his wife. He paid the money back after it became public.

National security adviser H.R. McMaster's departure has been expected for weeks. Sources say McMaster and Mr. Trump have clashed over policy -- something the commander in chief said he relishes.

"It's tough. I like conflict. I like having two people with different points of view and I certainly have that," Mr. Trump said. "And then I make a decision. But I like watching it. I like seeing it. And I think it's the best way to go. I like different points of view."

Mr. Trump's pick to take McMaster's place is former U.S. ambassador to the United Nations John Bolton, whose foreign policy ideas are much closer to those of the president.

Secretary of Housing and Urban Development Ben Carson has also come under fire recently for spending $31,000 on a dinning room set for his office. The order was eventually canceled.