Article VI, Section 2 of the Constitution provides:
The Senate shall be composed of twenty-four Senators who shall be elected at large by the qualified voters of the Philippines, as may be provided by law.
It is worthy to note that the composition of the Senate is smaller in number as compared to the House of Representatives. The members of this chamber are elected at large by the entire electorate. The rationale for this rule intends to make the Senate a training ground for national leaders and possibly a springboard for the presidency. It follows also that the Senator, having a national rather than only a district constituency, will have a broader outlook of the problems of the country, instead of being restricted by narrow viewpoints and interests. With such perspective, the Senate is likely to be more circumspect, or at least less impulsive, than the House of Representatives.
The qualifications for membership in the Senate are expressly stated in Section 3, Art. VI of the Constitution as follows:
No person shall be a Senator unless he is a natural-born citizen of the Philippines, and on the day of the election, is at least thirty-five years of age, able to read and write, a registered voter, and a resident of the Philippines for not less than two years immediately preceding the day of the election.
It is worthy to note that the age is fixed at 35 and must be possessed on the day of the elections, that is, when the polls are opened and the votes cast, and not on the day of the proclamation of the winners by the board of canvassers.
With regard to the residence requirement, it was ruled in the case of Lim v. Pelaez that it must be the place where one habitually resides and to which he, after absence, has the intention of returning.
The enumeration laid down by the Constitution is exclusive under the Latin principle of expressio unius est exclusio alterius. This means that Congress cannot anymore add additional qualifications other than those provided by the Constitution.
Only the Senate has the power to approve, via a two-thirds supermajority, or denounce treaties, and the power to try and convict, via a two-thirds supermajority, an impeached official.