To date, senate elections have coincided with elections to the lower house, but the prime minister may advise the king to call elections for one house only. While the
Congress of Deputies is chosen by
party list proportional representation, the members of the senate are chosen in two distinct ways: popular election by
limited voting and appointment from regional legislatures.
Directly elected members Most members of the senate (currently 208 of 266) are directly elected by the people. Each
province elects four senators without regard to population. Insular provinces are treated specially. The larger islands of the
Balearics (Baleares) and
Canaries (Canarias)—
Mallorca,
Gran Canaria, and
Tenerife—are assigned three seats each, and the smaller islands—
Menorca,
Ibiza–Formentera,
Fuerteventura,
Gomera,
Hierro,
Lanzarote and
La Palma—one each;
Ceuta and
Melilla are assigned two seats each. This allocation is heavily weighted in favor of small provinces;
Madrid, with its 6.5 million people, and
Soria, with 90,000 inhabitants, are each represented by four senators. In non-insular constituencies, each party nominates three candidates. Candidates' names are organized in columns by party on a large (
DIN A3 or larger)
ochre-colored ballot called a
sábana or
bedsheet. Each voter may mark up to three candidates' names, from any party. This is the only occasion when Spanish voters vote for individuals rather than a
party list.
Panachage is allowed, but typically voters cast all three votes for candidates of a single party. As a result, the four senators are usually the three candidates from the most popular party and the first placed candidate from the next most popular. Before 2011, a party could not choose the order of its candidates on the ballot paper; candidates were sorted alphabetically by
surname. When a party did not get all three of its candidates elected, this arrangement favored candidates with surnames early in the alphabet. This was the case for 2nd placed parties in every province and for both parties in tight races when voters did not vote for three candidates of the same party (
panachage).
Regional legislatures-appointed members The legislative assembly of each
autonomous community of Spain appoints a senators to represent the community, with one senator per one million citizens, rounded up. Demographic growth increased the combined size of the regional appointed senators from 51 to 57 since 1983.
Conventionally, the proportions of the regional senators mimic their legislative assemblies. However, autonomous communities have considerable leeway, and a motion to appoint the regional senators often requires no more than a
plurality: ==Composition==