Israel's declaration that Palestinian leader Yasser Arafat is persona non grata after failing to stop a rash of suicide bombers on Israeli territory is forcing U.S. officials to take another look at their relationship with the errant leader and their ability to do business with him.

On Sunday, Secretary of State Colin Powell said Arafat must rise to the challenge presented by militants in his midst and bring them to justice.

"So far he hasn't done enough to respond to this challenge. And we have been saying to him directly, you've got to do something about this or else we're not going to go anywhere," Powell said on Fox News Sunday

Officials say Powell has told European leaders to stop meeting with Arafat altogether and to "keep his feet to the fire" to rein in militant groups.

On Friday, President Bush demanded Arafat demonstrate his authority by cracking down on terrorists that have brought Israel and the Palestinian Authority to the brink of war. 

The pressure on the terrorist-cum-diplomat is mounting.

"He is definitely in a bind, he is isolated, even in the European sense," said Peter Huessy, president of the GeoStrategic Analysis, a defense consulting firm.  "I think he's lost his authority." 

For his part, Arafat — under the gun of Israeli forces pounding Gaza Strip and West Bank territories — ordered the arrest of over 150 Hamas and Islamic Jihad activists.  The move sparked demonstrations among Palestinians who see Hamas as the closest thing they have to a defending military force.

In a televised speech Sunday, Arafat ignored the protests and ordered "the complete cessation of all military activities," including those coming from Israel.  He said he would arrest militants who continue to mount suicide bombings.

Not Enough Anymore

Arafat's response, however, may be too little too late. Israeli Foreign Minister Shimon Peres, who won a Nobel Peace Prize with Arafat for the now-crumbling Oslo Peace Accords in 1994, called Arafat "irrelevant" to any further peace talks.

The United States appears to be coming around to that position, but the quandary it and Israel  face is what to do once Arafat is no longer a player in the Mideast peace process.

"The dilemma in the U.S. is we can't live with him and we can't live without him," said Georgetown University Professor Casimir Yost.  Yost said no Palestinian leaders have been identified as possible successors to Arafat.

Negotiations, however, are already at a standstill.  State Department officials announced Friday that U.S. Marine General Anthony Zinni, President Bush's peace envoy in the Middle East, will return home to the United States for consultations with Washington officials and will go back to the region after the holidays. 

"With General Zinni's withdrawal, I think (Arafat's) days are numbered," said Weekly Standard editor Bill Kristol.  "Arafat's rule of the Palestinian Authority could be near an end."

That end will likely be decided by the United States and it could be a tricky one.

"I don't think American officials are going to cut (Arafat) off officially – that would be completely perceived as following Israeli policy.  Besides, creating a vacuum of power in the Middle East would be totally against American policy," said Yossi Shain, an Israeli and visiting professor at American University.

Yost added that if Arafat leaves and the Israelis destroy whatever territories the Palestinians have been granted, "the U.S. will be blamed for it."

Fox News' Teri Schultz contributed to this report.