Complex sentence: While Abdulilah can be a candidate for the throne by virtue of seniority, his ill-starred government career (he was twice removed from governorships) leaves questions about his competency.
Split into simpler sentences: While Abdulilah can be a candidate for the throne by virtue of seniority, he has some drawbacks, such as his ill-starred government career. Since he was twice removed from governorships, there are questions about his competency.