Even if there were a draft, you don’t abandon your brothers. This is (far) above politics.
When there was a draft, you could apply for “conscientious objector” status. Some conscientious objectors are unwilling to serve the military in any capacity, while others accept noncombatant roles or civilian service instead of military service. Alternatives to military or civilian service include serving an imprisonment or other punishment for refusing conscription. Choosing one of those alternative is honorable. Muhammed Ali was an example of someone who honorably refused to serve. He went to jail for his convictions and lost years of fighting during the peak of his boxing career. This cost him millions of dollars as well as his freedom. Many people, myself included, respect him for having the courage of his convictions.
Refusing legal orders in a combat situation is about as low as you can go. Anyone who does it is a contemptible coward, a cur, who should be shot summarily.