party is known as the minority party. The president pro tempore, committee chairs, and some other officials are generally from the majority party. Whenever the elected members of the minority constitute less than nine members, the Constitution provides for the certification of additional "add-on" minority Senators, who will serve in an at-large capacity. Such was the case after the 2004 elections, when four defeated Popular Democratic Party (PPD) Senate candidates, one at-large, and three district candidates, were added on as at-large Senators, joining the five PPD Senators who had achieved election in their own right. This constitutional guarantee of a minimum legislative minority representation is unique to Puerto Rico among all legislatures under the American flag, incorporating an element of proportionality usually found only in proportional representation bodies. Officers The Senate is served by several officers with and without voting powers, which are elected from within and outside its ranks. Of these, only the president was established by the Constitution; all other officers were established by internal rules adopted by the Senate. Only the president and president pro tempore have voting powers as all are elected from within. Non-voting officers are elected from outside Senate ranks and simply assist in internal procedures and clerical tasks, and in the observance of internal rules, laws, and the Constitution. Typical non-voting officers include the secretary, the sergeant-at-arms, and other officers appointed by the different commissions as part of their own internal affairs. President of the Senate The president is the highest-ranking officer and the presiding officer of the Senate. The post was created by Article III of the Constitution of Puerto Rico which establishes that, "The Senate shall elect a President [...] from among [its] members." The president is substituted by the president pro tempore in his absence. Its counterpart in the House is the speaker. The current president is José Luis Dalmau, senator at-large from the Popular Democratic Party of Puerto Rico. President pro tempore The president pro tempore is the second highest-ranking officer of the Senate and substitutes the president of the House in his absence. Its counterpart in the House is the speaker pro tempore. The current president pro tempore is Marially González Huertas, senator for District V Ponce from the Popular Democratic Party. Party leaders Each party elects floor leaders denominated "majority leader" or "minority leader", accordingly, as well as a "majority whip" or a "minority whip". Floor leaders