WASHINGTON — Treasury Secretary Janet L. Yellen warned on Friday that she would have to begin employing “extraordinary measures” on Thursday to continue paying the nation’s bills if lawmakers did not act to raise the statutory debt limit and that her powers to delay a default could be exhausted by early June.Ms. Yellen’s letter to Congress was the first sign that resistance by House Republicans to lifting the borrowing cap could put the U.S. economy at risk and signals the beginning of an intense fight in Washington this year over spending and deficits.“Failure to meet the government’s obligations would cause irreparable harm to the U.S. economy, the livelihoods of all Americans and global financial stability,” Ms. Yellen wrote.Ms. Yellen said on Friday that considerable uncertainty surrounded how long she could use measures to delay a default. She said she would begin suspending n …
