In the grand theater of modern finance, where the audience has long since stopped expecting coherence and started settling for spectacle, the U.S. Treasury Department delivered another crowd-pleaser. Longer-term bond yields took a modest dip after officials announced they would at least double the size of their government debt repurchases. The 30-year yield “plunged” from 5.26% to as low as 5.18%. The 10-year, that ever-reliable barometer of mortgage rates and general economic anxiety, managed a far less dramatic slide from 4.68% to 4.64%. Stocks opened a touch higher, because of course they did. Markets love a good story about the grown-ups stepping in to tidy up the mess they helped create.