对市场至关重要的问题：美国就业塌方的原因是什么？

Core Viewpoint - The U.S. job market is cooling significantly, raising debates on whether the issue stems from a lack of workers or a decline in job demand, which directly impacts Federal Reserve's interest rate decisions [1][2]. Group 1: Supply Shortage Perspective - The labor force participation rate has dropped by 0.4 percentage points over the past three months, marking the largest decline in eight years, indicating reduced labor supply [3]. - Morgan Stanley's chief economist suggests that the slowdown in job growth is not contradictory to the low unemployment rate, especially considering immigration controls [3]. - Data shows a reduction of approximately 1 million foreign-born workers over the past three months, which the White House cites as a success of its immigration policies [3]. - Federal Reserve Chairman Powell indicated that as long as the unemployment rate does not rise significantly, the Fed will overlook the recent hiring slowdown [3]. Group 2: Demand Weakness Perspective - Citigroup's economist emphasizes that while immigration reduction has an impact, the details suggest that demand weakness is worsening [4]. - Analysts, including those from Bloomberg, argue that the report's data on foreign-born and native-born labor may contain statistical biases, as the sudden increase in native-born labor seems unrealistic [4]. - Analysts are focusing more on hiring data from business surveys, which were significantly revised down for May and June, to assess labor market conditions [4][5]. - Different analysts have drawn varying conclusions regarding the performance of industries heavily reliant on immigrant labor, with some indicating weakness in construction, manufacturing, and leisure sectors [5].