Why can't Taiwanese government protect her citizens?

How could the government allow 馬英九 to run for president when

1. 馬英九 has American permanent residence status, perhaps Chinese, British and American citizenship?
2. 馬英九 lied openly about so many things, including 特別費?
3. 馬英九 has so many court cases pending. The evidence is overwhelming that he is guilty in many of these cases, just as the evidence is damming that he deposited 特別費 into his personal account.
   

The government should protect its citizens with a thorough investigation on 馬英九 using standards befitting a presidential candidate. If we have a normal government, 馬英九 should be disqualified as a presidential candidate. He should be in jail.