This article focuses on the role of Doctor Luis Merlo de la Fuente as an arbitrista–a political advisor and proposer of solutions–who served as senior judge of the Royal Audiencia of Santiago de Chile and acted as interim governor of the kingdom for six months between 1610 and 1611. After returning to Lima to serve on the Audiencia of that city, between 1617 and 1636 he wrote at least five memorials addressed to the Crown, offering advice on how to conduct and win the Arauco War. Rather than analyzing the content of his proposals, this study examines his activities as a producer and mobilizer of information, as well as his efforts to build and sustain personal and political networks aimed at influencing colonial and imperial policies on Chile–an effort in which he ultimately failed, but which reveals the mechanisms of informal political advocacy within the Spanish Empire.Este artículo se centra en la faceta de arbitrista del doctor Luis Merlo de la Fuente, quien fuera oidor decano de la Real Audiencia de Santiago de Chile y gobernador interino de dicho reino por seis meses entre 1610 y 1611. Este al volver a Lima (donde asumió como oidor de su Audiencia) y entre 1617 y 1636 escribió al menos cinco memoriales o arbitrios en los que pretendió aconsejar a la Corona en cómo hacer y vencer en la Guerra de Arauco. No obstante, lo que nos interesa reconstituir no son tanto sus argumentos, sino su actividad como gestor de información y constructor de redes personales y políticas con las que pretendía influir, aunque fracasara en ello, en las políticas de la monarquía respecto de Chile tanto a nivel metropolitano como virreinal.