What is the rationale for the harmonization of international accounting standards? Why is the SEC, once so reluctant to accept IAS, now very willing to allow firms using IFRS to issue securities in...

What is the rationale for the harmonization of international accounting standards? Why is the SEC, once so reluctant to accept IAS, now very willing to allow firms using IFRS to issue securities in the U.S. stock market without reconciling to U.S. GAAP?