The intensifying debate over when the Federal Reserve raises interest rates is little more than a sideshow when it comes to the ability of the U.S. to borrow.

For all the concern fixed-income assets will tumble once the central bank boosts rates, the Treasury Department still managed to get investors to submit $3.4 trillion of bids for the $1.12 trillion of notes and bonds sold this year, according to data compiled by Bloomberg. That represents a bid-to-cover ratio of 3.06, the second-highest on record and up from 2.88 in all of last year.

Attracting investors is critical for the U.S. as it finances a debt load that has more than doubled to almost $18 trillion since before the financial crisis. The appeal of Treasuries was on display last week as benchmark 10-year notes rallied the most since March while investors sought a haven amid rising concern over the health of a Portuguese bank.