Sen. Charles Grassley, the ranking Republican on the Senate Finance Committee, is a busy man. The Iowan spends his time supervising private colleges, private charities, churches and now ministries. Oh, and when he has time, he’s supposed to be supervising the federal budget.

Mr. Grassley is threatening to subpoena ministries run by Kenneth Copeland, Paula White, Creflo Dollar and Eddie Long – four of six televangelists under investigation for using their tax-exempt status to support avaricious lifestyles. Lawyers for the Copeland and Dollar organizations have told the Senate that they do not plan to comply with a probe on grounds that it threatens religious rights.

Before that, Mr. Grassley wrote to the presidents of 136 colleges demanding detailed information on their endowments, finances and financial aid policies. He had already introduced legislation mandating that schools with endowments of more than $500 million spend at least 5 percent each year.

Harassment of private organizations, especially nonprofits, has been a hallmark of Mr. Grassley’s record for the past year and previously in his tenure as chairman of the Finance Committee from 2001 to 2007. Somehow a federal budget of $2.9 trillion a year, with a national debt of $9 trillion increasing at $500 billion a year, just doesn’t keep him busy.

Congress has bigger financial problems to worry about. In 2002, economists Kent Smetters and Jagadeesh Gokhale prepared a report for the president’s annual budget examining the generational imbalances facing the federal government. They calculated that it would cost $44.2 trillion to put federal fiscal policies on a sustainable path. That’s the difference between all the federal government’s future obligations – mostly for Social Security and Medicare – and the revenue it’s expecting. Each year the federal government fails to enact reforms, the imbalance grows by about $1.6 trillion.

Yet Mr. Grassley seems to think his position on the Finance Committee empowers him to be a free-ranging ombudsman for the entire American economy. In 2005, he investigated the trustees of American University after they fired president Benjamin Ladner for lavish expense spending. In 2006, he hectored oil companies over their rising profits.

The Senate Finance Committee is authorized to oversee U.S. debt, customs and ports, the deposit of public moneys, intergovernmental revenue sharing, federal health programs, Social Security, reciprocal trade agreements, revenue measures, tariffs and import quotas and transportation of dutiable goods.

That’s a lot of ground to cover, but each element of the committee’s jurisdiction relates to the federal government’s revenues and expenditures. The committee is in charge of the finances of the federal government, not those of every institution in the United States.

Mr. Grassley’s investigation of the televangelists may be his most troubling crusade to date, as the U.S. has a longstanding commitment to the separation of church and state, and politicians simply have no authority to investigate how religious organizations arrange their affairs.

All those investigations of private churches, charities, colleges and businesses are also outside the proper jurisdiction of the Senate Finance Committee, and indeed that of Congress. Congress’ job is to manage the federal government. The Constitution grants it no authority to investigate, subpoena and harass private organizations.

Social Security, Medicare and Medicaid already account for more than 40 percent of federal spending, and they’re projected to rise to 70 percent in barely two decades. Chuck Grassley and his colleagues on the Finance Committee presumably should have something to say about that. Do they?