NO law is complete of itself.
Even the Constitution, a marvel of simplicity, required many court decisions to determine exact meanings when applied to particular situations.
As legislation was evolved to meet the growing complexities of an industrial economy, Congress thought it necessary to go further than legislation and provide for administrative tribunals with authority to interpret and power to enforce such legislation.
While the American theory of government by administrative tribunals had its origin in the nineteenth century, it remained for the New Deal to bring government by regulation into full flower.
Consequently, it has been justly said that we no longer have a government of laws but a government of agencies.
For proof of this, we can look back on a few of many decisions of the first National Labor Relations Board under the Wagner Act. This agency seemed determined to prove that the law never meant what it said but that it meant only what the NLRB said it said.