WASHINGTON -- At a Thursday morning news conference, President George W. Bush scolded Congress for not passing a bill that would provide health care coverage for poor children.

Bush Challenges Dems On Child Spending Bill

"Congress is putting health care for poor children at risk," Bush said. "If they fail to [pass a bill by Sept. 30], more than a million children could lose health coverage. Health coverage for these children should not be held hostage while political ads are being made and new polls are being taken."

Bush said he will veto the bill Congress is considering, which is to raise the eligibility for the State Children's Health Insurance Program (S-CHIP) to include children from families that make $80,000 per year.

"That's the not the intent of S-CHIP," Bush said. "I believe this is a step toward the federalization of health care."

Bush has said that S-CHIP was designed to ensure that poor children without health insurance receive medical care. He said that his budget increases funding for the poor children in S-CHIP.

Bush has been taking questions on the economy and the war in Iraq.

"The fundamentals of economy are strong," Bush said. "I'm optimistic about economy. I would be pessimistic if Congress had its way and raised taxes. We're keeping fiscally responsible."

"There is no question there are some unsettling times in the housing markets and credits associated with the housing market," Bush said.

Some economists suggest the housing slump could lead to a recession even in spite of action earlier this week by the Federal Reserve to cut short-term interest rates by a half-percentage point.

Pressed on whether he was concerned that the nation was nearing a recession, Bush said, "You need to talk to an economist."

Bush said that there had to be a change in security in Iraq in order for there to be reconciliation, and that the Iraqi government needed to pass an oil-revenue sharing plan.

Bush Thanks Johanns

Bush officially said farewell to Agriculture Secretary Mike Johanns in a Rose Garden ceremony Thursday morning.

"Mike has been an outstanding member of my Cabinet," Bush said. "I admire the fact that he's not only a decent person and an honest person, but a person that (gets things done.)"

Deputy Agriculture Secretary Charles Conner was named acting agriculture secretary.

"I thank him from the bottom of my heart," Bush said. "I couldn't have asked for a better secretary of agriculture."

Johanns thanked the staff at the department and thanked Bush for the opportunity to serve.

"It has been a great honor for me and for the people of Nebraska to serve you," Johanns said. "The decision to leave this post has not been an easy one."

"Even as I look forward to returning to the good life of Nebraska, I look back at what has been a dream come true for a farmer's son," Johanns said.

A Republican official said Johanns is resiging from his Cabinet post to run for a U.S. Senate seat in Nebraska.

The official said Johanns is planning to announce his bid to replace retiring Republican Sen. Chuck Hagel as early as Monday.

Johanns, a former Nebraska governor, has refused to say publicly if he is even interested in Hagel's Senate seat. But his spokeswoman said he will make a decision soon.

The White House said Bush will support Johanns no matter what he decides.

A run by Johanns would make him the fourth declared Republican candidate for the Senate seat. Democrats are hoping that Bob Kerrey, also a former Nebraska governor and former U.S. senator, will return to Nebraska politics.

Bush earlier this week proposed filling one Cabinet vacancy -- the position of attorney general -- with retired federal judge Michael Mukasey, who was nominated to succeed Alberto Gonzales.

Inside the White House, Bush has seen the departures recently of longtime advisers Karl Rove and Dan Bartlett. Press secretary Tony Snow's last day was last Friday.