Claims

The US government will not default on its treasury obligations; when push comes to shove, government prioritizes interest payments and debt redemption over government wages, military compensation, and park closures, making a default scenario virtually impossible.

If Trump administration officials seriously pursue the idea of restructuring foreign-held US debt (reducing coupon for foreign holders), it would trigger an immediate and severe shock to dedollarization, converting the long-term gradual process into a rapid capital flight that would be economically historic and frightening.

If the government's policy objective is to extend the duration of federal debt liabilities (to lock in borrowing costs), then having Treasury buy back short-duration bonds and reissue long-duration bonds is the best approach—but if this is the objective, it should be stated explicitly rather than hidden behind passive flow mechanics.

Trump administration's effort to mandate S&P 500 index exposure in new retirement accounts (Trump accounts) combined with a cap of 10 basis points in fees is a government mandate for index weighting—the opposite of market-based competition and a signal that the administration wants to concentrate capital in large-cap equities.

Vanguard and other index providers choose market-cap weighting for bond indices because it is 'easy to explain,' not because it is theoretically optimal; but this choice is now influencing outcomes at the political level (Fed policy, government decisions) because passive flows are large enough to move markets.