Key Points
— Chilean President José Antonio Kast chose Argentina for his first foreign trip since taking office March 11 — meeting Milei at Casa Rosada on April 6 to formalise cooperation on mining, energy, border infrastructure, and organised crime
— The two leaders agreed to digitise Andean border crossings to cut wait times, share intelligence on transnational crime, and integrate their mining and energy sectors — with Kast expressing particular interest in Argentina’s booming Vaca Muerta shale and copper pipeline
— The alliance represents the clearest right-wing ideological alignment in South America since the Piñera-Macri era — and is designed to counterbalance Brazil’s Lula, extend into Bolivia, Paraguay, and Uruguay, and align the Southern Cone with Washington’s hemispheric strategy under Trump
When Argentina’s president and Chile’s president pose together holding a chainsaw — as Milei and Kast did in December — the symbolism is not accidental. These are two leaders who believe the state is the problem, the market is the solution, and Washington is the partner. Monday’s summit made that shared conviction operational.
The Milei Kast alliance became concrete on Monday when Chile’s José Antonio Kast arrived at Argentina’s Casa Rosada for an expanded bilateral meeting — his first foreign trip since inauguration. Accompanied by Chile’s foreign minister, security minister, public works minister, and trade undersecretary, the delegation’s composition signalled that this was not a courtesy call. It was an operational planning session for a right-wing Southern Cone bloc.
Mining: Chile’s Expertise Meets Argentina’s Untapped Deposits
The economic centrepiece of the meeting was mining integration. Kast called it “a historic moment” and said Chile could contribute “knowledge and logistics” to Argentina’s rapidly expanding mining sector. The context makes this more than rhetoric. Chile’s copper output has fallen to a nine-year low as ore grades decline at mature deposits. Meanwhile, Milei has scrapped export taxes on mining, offered 30-year fiscal stability through the RIGI investment regime, and is pitching Argentina as a new frontier on the same Andean copper belt that built Chile’s wealth.
Argentina’s mining pipeline now includes over $14 billion in copper, lithium, and gold projects across San Juan, Catamarca, Salta, Mendoza, and Jujuy. Chile’s mining expertise — in processing, logistics, and environmental management — is precisely what Argentina’s nascent sector lacks. For Chilean companies like Codelco and SQM, Argentine deposits offer growth that their depleted domestic reserves cannot. Bilateral trade between the two countries reached $7.98 billion in 2025, and mining integration could push that figure significantly higher.
Energy: Vaca Muerta’s Pull
Chile is a net energy importer. Argentina, thanks to Vaca Muerta, is becoming an energy exporter. The complementarity is obvious and increasingly urgent — the Strait of Hormuz crisis has pushed global energy prices to levels that make cross-Andean gas and oil pipelines economically viable in ways they were not a year ago. Kast’s government has signalled it wants to diversify Chile’s energy supply away from dependence on volatile global markets, and Argentina is the nearest, cheapest source.
Security and Borders: 5,300 Kilometres of Shared Frontier
Both leaders framed security cooperation as existential. Kast said organised crime “does not respect laws and has many resources” and called for a multi-country alliance including Bolivia. Milei’s government has already revoked the political refugee status of Galvarino Apablaza — a former Chilean guerrilla accused of masterminding the 1991 assassination of right-wing senator Jaime Guzmán — and is cooperating in the hunt for the fugitive, whose arrest warrant failed last week when he fled before police arrived.
On the border itself, both governments agreed to digitise customs and immigration at Andean crossing points — where trucks and tourists routinely wait hours — to cut costs and speed the flow of goods. Chile and Argentina share roughly 5,300 kilometres of frontier, and modernising it is a prerequisite for the mining and energy integration both leaders want.
The Geopolitical Map: Lula Out, Trump In
The Milei Kast alliance is not only bilateral — it is designed to reshape the Southern Cone’s power balance. Kast explicitly named Bolivia, Paraguay, and Uruguay as countries he wants to pull into the axis. Paraguay’s Santiago Peña is already closely aligned with both Milei and Washington, having signed a Status of Forces Agreement with the US. Bolivia’s new government has been pursuing its own rapprochement with Washington, including DEA cooperation. Uruguay under Yamandú Orsi is more centrist but shares the economic pragmatism that defines the bloc.
The absent figure is Brazil’s Lula. Both Milei and Kast are close allies of Donald Trump and attended the “Shield of the Americas” summit on March 7 — a security alliance of 17 mostly right-leaning Latin American governments that pointedly excluded Brazil, Colombia, and Mexico. Lula skipped Kast’s inauguration. The Buenos Aires Times reported that the Milei-Kast meeting is explicitly intended to “counter the regional influence of Brazilian President Luiz Inácio Lula da Silva’s left-wing government.” For investors, the signal is that the Cono Sur is splitting into two gravitational fields — a market-friendly, US-aligned southern bloc and a more state-directed, non-aligned Brazilian sphere — and capital allocation decisions in mining, energy, and infrastructure will increasingly need to account for which orbit a country occupies.