Parroting things without actually thinking about them doesn’t generally produce any interesting insights. As long as a country’s debt is denominated in its own currency and it has control over issuing that currency, it can create more of it to cover any outstanding obligations. This means there’s no risk of default because the government can simply print money to pay off its debts. That’s how US is able to have national debt of $34.4 trillion right now. If The Economist thinks that Russia’s financial reserves will be exhausted in five years or so, then they have some explaining to do regarding the US.