The reason Turkey has to borrow in someone else's currency is that their own currency doesn't have the credibility it needs to support low interest rates, so if

The reason Turkey has to borrow in someone else's currency is that their own currency doesn't have the credibility it needs to support low interest rates, so if they want to borrow at affordable rates to boost their economy, they need to use foreign currency. If the US keeps up the deficit spending, it will either need to pay a huge amount of money on debt service, or it needs to monetize its debt - which means credibility will be lost and new debt will be more expensive. Either way, it's not a free lunch.