Will a soldier, who kills others while defending the country during a dispute, be admitted to Jannah (Paradise)?
Yes, they will be admitted to Jannah, if they die as a Muslim. However, if a Muslim has committed (Part No. 1; Page No. 733) major sins, other than Shirk (associating others with Allah in His Divinity or worship), and dies without performing Tawbah (repentance to Allah), their affair will be left to the Will of Allah (Glorified be He). This is the view held by
Ahl-ul-Sunnah wal-Jama`ah (adherents to the Sunnah and the Muslim mainstream) based on the Qur'anic Ayah (verse) in which Allah (Glorified and Exalted be He) says:
Verily, Allâh forgives not that partners should be set up with Him (in worship), but He forgives except that (anything else) to whom He wills
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.