Central bankers are unelected officials but they have always had an outsized impact on economies and the welfare of citizens. After the Great Recession, they have gained even more power and influence as they brought the global financial system back from the brink. Paul Tucker, former deputy governor for the Bank of England who had a front seat as the financial crisis unfolded, said central banks have emerged as a “third great pillar of unelected power alongside the military and the judiciary.” His book , Unelected Power: The Quest for Legitimacy in Central Banking and the Regulatory State , examines the enhanced role of central bankers and offers principles for them to follow to be good stewards. Tucker, who is also chair of The Systemic Risk Council, joined the Knowledge at Wharton show on SiriusXM , to share his insights. An edited transcript of the conversation follows.   Knowledge at Wharton: Considering the title of the book, should central bankers be elected officials?…