WASHINGTON, Sept. 12 — Stung by suggestions that President Bush had hurt
himself politically by delaying his return to Washington on Tuesday, the
White House asserted today that Mr. Bush had done so because of hard
evidence that he was a target of the terrorists who hijacked airliners
and slammed them into the World Trade Center and the Pentagon.

Ari Fleischer, the White House press secretary, said this afternoon that
officials had "real and credible information" that the White House, not
the Pentagon, had been the original target of American Airlines Flight
77, which was hijacked about 45 minutes after leaving Dulles
International Airport in Virginia.

Another senior official said that after that plane hit the Pentagon,
a chilling threat was phoned to the Secret Service.

"Air Force One is next," the official quoted the caller as saying.
The threat was accompanied by code words that indicated knowledge
of White House procedures, the official said.

Karl Rove, Mr. Bush's adviser, said in an interview this morning that Mr. Bush
had twice on Tuesday — in the morning and in the early afternoon — argued
strenuously that he should return immediately to the capital. Mr. Rove reported
that the Secret Service insisted that the situation  here was "too dangerous, too unstable"
for the president to come to Washington.

"We are talking about specific and credible intelligence," Mr. Rove
said, "not vague suspicions."

But neither Mr. Rove nor other officials explained why this information was not made
public on Tuesday. Partly because it was not, Mr. Bush was criticized for spending the
day traveling a zigzag route from Sarasota, Fla.; to Barksdale Air Force Base near
Shreveport, La.; then to Offutt Air Force Base in Omaha; then back to Washington.
He did not land at the White House until 7 p.m., almost exactly 10 hours after he
learned of the first attack.

In addition, much remained unclear about the sequence of events. Some officials
suggested that airplanes other than the four known to have been hijacked had in
some unspecified way jeopardized the safety of President Bush.

On television, in newspapers and in animated discussions in offices
across the country, Mr. Bush's conduct was compared unfavorably with
that of Mayor Rudolph W. Giuliani of New York, who went to the scene of
the attacks in Lower Manhattan; to John F. Kennedy, who stayed in
Washington throughout the Cuban missile crisis of 1963, when many feared
that nuclear war was imminent, and to Defense Secretary Donald H.
Rumsfeld, who remained at the Pentagon after it was hit and for a time
helped in the evacuation of the dead and wounded.

The president's conduct, said an article this morning in the staunchly
conservative Boston Herald, "did not inspire confidence."

The official who reported the threat to Air Force One, speaking on condition that
he not be identified, said Vice President Dick Cheney called the president early on
Tuesday and urged him not to return to Washington immediately.

According to the official, Mr. Cheney, a former secretary of defense,
suggested that Mr. Bush go to Offutt, which has excellent secure
communications that could be used to hold a video teleconference with
the National Security Council. A senior officer at the Pentagon said
that a preliminary stop had been made at Barksdale because it would be
unexpected by anyone tracking the president's plane.

"It would have been irresponsible of him to come back, pounding his
chest, when hostile aircraft may be headed our way," the official said.
"Any suggestion that he do so was ludicrous."

Still, Mr. Bush suggested exactly that at least twice, according to
notes Mr. Rove took and read to a reporter this morning.

As Air Force One, flying north from Sarasota, crossed over the Florida
Panhandle, Mr. Rove said, Mr. Bush made it clear that he wanted to go to
Washington and nowhere else. That would have been sometime between 10
and 11 a.m., after planes had hit the two Trade Center towers and the
Pentagon. The Pentagon attack, the third in the sequence, occurred at 9:45 a.m.

The other official said that Mr. Cheney was first told that the plane
heading for the White House might be an airliner, private plane or
helicopter loaded with explosives. But by the time Mr. Bush made his
first request to return to Washington, which was rebuffed by the Secret
Service, that plane was no longer any threat to the White House, since
it had hit the Pentagon.

Another hijacked plane, United Airlines Flight 93, plunged into a field
southeast of Pittsburgh about 10:10 a.m., and word of that crash took
some time to seep out. The security officers may still have considered
it unaccounted for, and hence a threat, when they warned the president.

But at 1:25 p.m., Mr. Rove's notes show, Mr. Bush turned to his chief of
staff, Andrew H. Card Jr., as Air Force One sat on the tarmac at Barksdale,
and renewed his demand to return to Washington. Mr. Rove quoted him as saying,
"The people of America will expect to see me and hear from me in Washington."
But the president's words, Mr. Rove said, were "saltier."

Again Mr. Bush was rebuffed. By then the Pittsburgh crash was big news on the
networks, and television anchors were starting to suggest, sometimes not very gently,
that Mr. Bush was absent at a time of national crisis.

So what constituted the threat at that point?

The senior official said that Mr. Cheney had originally been told there were six
airliners unaccounted for, presumably including the one that crashed near Pittsburgh.
It may have been headed for the White House before something — perhaps a bomb
explosion on board, perhaps a cockpit struggle — stopped it.

Presumably, the five other airliners continued to be regarded as a threat, but it is not
known for how long. Four were over the Atlantic, and they landed in Canada;
one was inbound from South Korea, and it landed in Alaska.

Exactly what times those planes landed is not known, but the FAA issued its order
to clear the skies at 9:40 a.m., three and a half hours before Mr. Bush insisted to
Mr. Card that he return to Washington.

Once the White House account of the threats to the president and the White House
was made public today, some steam went out of the criticism of Mr. Bush. Today's
comments on Capitol Hill, for example, were nearly all supportive.

Representative Randy Cunningham, a conservative Republican from
California who was shot down on his 300th mission as a Navy pilot over
Vietnam, said of Mr. Bush's journey on Tuesday: "It was done exactly as
it should have been done. Think what would have happened if we we had
lost the president."

Representative David Dreier, a moderate Republican, also from California, said,
"With this news of the White House and possibly Air Force One as possible targets,
it becomes very clear that he made the right decision."

Only a Republican senator from a Western state, unwilling to speak for the record
because, he explained, he wanted to "maintain a united front," offered any criticism.

"The president could have overruled the security people and come back
earlier, and maybe he should have," the senator said. "The Secret
Service works for him, after all, and not the other way around."