Every economy, no matter how complex, is built on three basic inputs, or factors of production: land, labor, and capital. Land includes natural resources like soil and minerals. Labor is the human effort that goes into production. Capital refers to the machinery, tools, and infrastructure used to produce goods and services.

No two countries are the same. Each has a different mix of these factors. This unique mix is called a country's factor endowment. A country like Canada has a vast amount of land, making it land-abundant. A country like Germany is known for its advanced factories and technology, making it capital-abundant. Another country might have a large population with limited capital, making it labor-abundant.

The Heckscher-Ohlin model helps explain international trade patterns based on these factor endowments. The core idea is simple: countries tend to export goods that make intensive use of the factors they have in abundance. At the same time, they import goods that require factors they have in scarcity.

For example, let's consider two countries: one is capital-abundant (let's call it Innova) and the other is labor-abundant (let's call it Manuplex). Innova excels at producing high-tech goods like commercial airplanes, which require a lot of capital—sophisticated factories, expensive machinery, and advanced research. Manuplex, with its large workforce, is better suited to producing clothing, which is labor-intensive.

According to the Heckscher-Ohlin model, Innova will produce and export airplanes to Manuplex. In return, Manuplex will produce and export clothing to Innova. Both countries specialize in what they do best, based on their unique factor endowments.

This specialization makes the global economy more efficient. But it also has a profound impact within each country, creating clear winners and losers. This is where economics spills over into politics.

The Stolper-Samuelson theorem explains how international trade affects incomes within a country. It states that opening up to free trade raises the income of a country's abundant factor and lowers the income of its scarce factor.

Let's return to our example. When Innova (capital-abundant) starts trading with Manuplex (labor-abundant), the demand for its airplanes increases. This benefits the owners of capital in Innova—the factory owners and investors—who see their profits and returns rise. However, Innova also begins importing cheaper clothing. This creates intense competition for Innova's domestic clothing industry. The workers in that industry, representing the scarce factor (labor), face downward pressure on their wages or even job losses.

The opposite happens in Manuplex. Its large labor force benefits from the increased global demand for clothing, leading to higher wages and more job opportunities. Meanwhile, its small class of capital owners faces new competition from imported airplanes, reducing their returns.

These economic outcomes create predictable political divisions. The groups that benefit from trade will lobby for free trade policies like lower tariffs and fewer import restrictions. The groups that are harmed by trade will demand protectionism to shield them from foreign competition.

In our capital-abundant country, Innova, we would expect to see owners of capital organizing to support free trade. They might form business associations or donate to pro-trade political parties. In contrast, labor unions would likely lobby for tariffs on imported goods to protect workers' jobs and wages. This creates a political cleavage based on factor endowments—a conflict between capital and labor.

The factor model provides a powerful lens for understanding why people in the same country can have such different views on globalization. It's not just about abstract economic principles; it's about how trade policy directly affects their livelihoods and creates fundamental political conflicts.