Historically, Trump's protectionist policies have led to increased stock prices for domestic industries, such as steel and aluminum. The raise in tariffs from 25% to 50% is likely to boost the US steel and aluminum industries, leading to higher stock prices for companies like US Steel and Alcoa. However, this move may also lead to retaliatory measures from other countries, potentially increasing market volatility. The overall impact on the stock market is expected to be positive, particularly for the materials sector, as Trump's policies aim to support domestic industries and create jobs. The 'America First' approach may also boost investor confidence in US-based companies, further driving up stock prices. Nonetheless, international trade implications and potential retaliatory measures from other countries should be closely monitored, as they may impact the overall market sentiment.