Growing tensions between the United States and Iran have renewed questions about what would happen if a major global conflict forced America to bring back compulsory military service.
President Donald Trump's latest remarks about the possibility of a future world war have brought renewed attention to the country's military draft system, which has remained inactive for more than five decades.
Although the United States currently relies on a volunteer military, the federal government maintains a system designed to identify people who could be called upon during a national emergency.
And under existing Selective Service procedures, there is a specific order in which Americans would be selected if compulsory military service were reinstated.
Who would be drafted first if World War 3 broke out?
According to the US Selective Service System, the first group eligible to receive induction orders would be men turning 20 during the calendar year in which a military draft takes place.
However, not every 20-year-old would automatically be required to serve.
A nationwide lottery would determine the order in which eligible individuals were called, using randomly selected dates of birth.
If the military required additional personnel, the draft would then move through older age groups.
Under the established selection system, the priority order would generally be:
This means that 18-year-olds would not necessarily be the first Americans called up, despite being among those required to register for Selective Service.
The system is intended to establish a defined order of selection rather than requiring everyone within the eligible age range to report simultaneously.
What has Donald Trump said about World War 3?
Trump's recent comments about international security have attracted attention amid tensions involving Iran and its nuclear programme.
During a press conference, the president reiterated his position that the United States would not allow Iran to obtain nuclear weapons.
He also suggested that a future American president whom he considered weaker could face the prospect of a major international war.
The remarks have contributed to public discussion about the possibility of a wider conflict and what military mobilisation might involve.
However, comments about a hypothetical future war do not mean that a military draft has been authorised.
There is no automatic requirement for the United States to introduce conscription simply because it becomes involved in a conflict.
Would all American men have to fight?
No. Even if a military draft were authorised, being registered with Selective Service would not automatically mean someone would be sent into military service.
Under existing federal requirements, almost all male US citizens and male immigrants aged 18 to 25 must register with the Selective Service System.
This includes many non-citizens living in the United States, including lawful permanent residents and certain undocumented immigrants.
However, registration and induction are two separate processes.
Registration places an individual in the system that could be used during a national emergency.
Induction would require additional legal authorisation, selection and eligibility assessments.
How would the military draft lottery work?
If Congress and the president authorised a draft, the Selective Service System would begin the process of identifying individuals for potential military service.
One of the central steps would be a national lottery.
Rather than selecting individuals according to their surname or location, the system would use randomly drawn dates of birth to establish the order in which eligible registrants could be called.
Each date would receive a random sequence number.
Those with birthdays assigned the earliest numbers would generally be considered before those with higher numbers, subject to the applicable age-priority rules.
The lottery would establish an order of selection, not an automatic requirement for every person whose birthday was drawn to join the armed forces.
What happens after someone is selected?
Individuals receiving an induction notice would be instructed to report for further processing.
They would undergo assessments designed to determine whether they were suitable for military service.
These evaluations could include physical and mental health examinations, along with other eligibility checks.
Someone who did not meet the required standards might be found ineligible for induction.
Selected individuals would also have opportunities to make claims for postponement, deferment or exemption under the applicable rules.
Only those who satisfied the necessary requirements would proceed into military service.
Who could be exempt from a military draft?
Several circumstances could affect whether an individual is required to serve.
According to Selective Service guidance, possible exemptions, postponements or alternative arrangements may involve:
Conscientious objectors may be considered for alternative service or non-combatant military duties, depending on their beliefs and the applicable classification.
Being a student, parent or caregiver does not automatically guarantee exemption.
Each claim would need to be assessed under the relevant legal requirements.
Could women be drafted into the US military?
Under the current Military Selective Service Act, the registration requirement applies to men rather than women.
Women can serve voluntarily in the US armed forces, including in combat roles, but are not currently required to register with Selective Service.
Congress would need to change the law to extend mandatory registration and potential conscription to women.
Consequently, the existing draft procedures are based on the registration of eligible men.
How quickly could a US military draft begin?
The Selective Service System has established mobilisation plans intended to deliver the first inductees to the military within 193 days of draft authorisation.
That period would allow time to activate the system, conduct the lottery, issue notices and assess individuals selected for potential service.
However, the 193-day figure is a planning target rather than a guarantee of exactly how long a future mobilisation would take.
The process would depend on the legal authorisation provided and the circumstances of the national emergency.
When was the last US military draft?
The United States last used compulsory military conscription during the Vietnam War era.
The country moved to an all-volunteer military in 1973, ending the practice of routinely drafting men into service.
Although compulsory induction stopped, the Selective Service registration system was subsequently restored in 1980.
Its purpose is to maintain a pool of potential recruits if the government ever determines that voluntary enlistment is insufficient to meet national defence requirements.
Is America bringing back the draft?
There is no indication from the Selective Service procedures themselves that a draft has been activated.
Reinstating compulsory military service would require action by Congress and the president.
A world war would not automatically trigger a draft without those legal steps.
Even if a major conflict occurred, the government would first have to determine whether additional military personnel were needed beyond those available through existing forces and voluntary recruitment.
For now, the established system provides an explanation of who could be selected first if conscription ever returned, rather than evidence that Americans are about to receive draft notices.
More information about registration, the lottery and possible exemptions is available from the US Selective Service System.
