In my opinion, being a president is so easy in that all you have to do are just two things. In my opinion, being a president is so easy that all you have to do are just two things.

To be sSpecifically, your country should ownpossess a super powerful military. Specifically, your country should possess a super powerful military.

Your original sentence is grammatically correct. Logically however, ‘possess’ would be a better word than ‘own’.

With a strong military, your country won't be invaded by others, and it'which is the foundation of any nation. With a strong military, your country won't be invaded by others, which is the foundation of any nation.

When linking together an independent clause to dependent clause, ‘which’ or ’that’ is preferable instead of ‘and’ . ‘And’ typically connects two clauses of equal value. I like to watch movies and go hiking. A nation is only as strong as its leader, and a leader is only as strong as his people.

With a lot of money, your country can develop theit’s economy, science and technology, education, and medical care and so onsystem. With a lot of money, your country can develop it’s economy, technology, education, and medical system.

I also believe that there are many people who canould be presidents, but the key is how they can get that position. The key difference between you and them is opportunity. I also believe that there are many people who could be president. The key difference between you and them is opportunity.

Even cutting offexcluding more than half the population of one country, there are still many people who are capable of being a president, let alone other government officials. Even excluding more than half the population of one country, there are still many people who are capable of being a president, let alone other government officials.

"Cutting off" does not fit in this sentence.

Even cutting off morif we assume thant half the population of one country is incompetent, there are still many people who are capable of being a president, let alone other government officials. Even if we assume that half the population of one country is incompetent, there are still many people capable of being a president, let alone other government officials.

So neverdo not admire those who have a higher position than you, they are not necessarily asmore capable asthan you, you just doidn't have thate same opportunity. So do not admire those who have a higher position than you, they are not necessarily more capable than you, you just didn't have the same opportunity.

I rewrote to sound a bit more native.

So never admire those who have a higher position than you, they are not necessarily as capable as you, y. You just don'idn’t have thateir opportunity. So never admire those who have a higher position than you, they are not necessarily as capable. You just didn’t have their opportunity.