Calling Iraq "the most important challenge," Crocker said joining the foreign service "does not mean you can choose the fight."
"It's not for us to decide if we like the policy or if the policy is rightly implemented," said Crocker. "It's for us to go and serve, not to debate the policy, not to agree with it."
Secretary of State Condoleezza Rice plans to send a cable to all U.S. embassies and missions abroad explaining the decision to launch the largest diplomatic call-up since Vietnam, State Department spokesman Sean McCormack told reporters soon after Wednesday's meeting.
Rice was making clear in the cable that foreign service officers have an obligation to uphold the oaths they took to carry out the policies of the U.S. government and be available to serve anywhere in the world, McCormack added.
Under the new order, 200 to 300 diplomats have been identified as "prime candidates" to fill 48 vacancies that will open next year at the U.S. Embassy in Baghdad and in Iraqi provinces. Those notified have 10 days to accept or reject the offer. If not enough say yes, some will be ordered to go.
Only those with compelling reasons, such as a medical condition or extreme personal hardship, will be exempt from disciplinary action. Diplomats forced into service in Iraq will receive the same extra hardship pay, vacation time and choice of future assignments as those who have volunteered.
McCormack has said that since the call-up to fill the 48 vacant Iraq posts was announced last Friday, 15 diplomats have volunteered to work there.
In 1969, an entire class of entry-level diplomats was sent to Vietnam. On a smaller scale, diplomats were required to work at various embassies in West Africa in the 1970s and 1980s.
Crocker is scheduled to travel to Istanbul, Turkey, on Friday evening for a regional conference the next day with Iraq's neighbors. He has been on a tour of Arab countries in the Mideast, trying to persuade more of them to dispatch ambassadors to Iraq.