In the latter years of the eighteenth century, when some of the British colonies in America decided that rule from the other side of the Atlantic was counter-productive to their own liberty and economic advancement, their revolution began but the Industrial Revolution had yet to commence. Travel was by sailing ship, horse-drawn carriage or on foot. Information was transmitted either verbally or by written word, both carried by a human. Lighting was done by candle, kerosene hadn't even come into use. Heat was supplied by wood or coal.
Obviously under these circumstances discussions between legislators and other government officials often had to be face-to-face, although much of their intercourse was by post, as we may see from publications of their correspondence. This meant that they had to meet in a central location. The Rome of the new country was the District of Columbia, created from the beginning as the focus of the fledgling federal government as a replacement for the previous temporary centers in New York and Philadelphia. Strangely,existing cities in the new states became capitals.
Initially, the congress met for only a portion of the year. Being a representative or a senator wasn't considered an occupation and most congressmen had to attend to the affairs that had gained them the prominence to be elected to office in the first place. As the federal government metastisized, more and more functions came to be performed in the capital, more offices were located there and the complex reached its present dimension, continuing to grow even now. The legislators, conducting their daily business in Washington, came to call the DC area home, visiting their nominal constituencies only on holidays, vacations, and during election campaigns.
But while the federal government was entrenching itself in the humid, once malarial Potomac River estuary, technology was changing transportation and communication in America. Eventually information could be sent by telephone, fax, television, computer, etc. It's now possible to carry on a conversation with a relative on the opposite side of the country, or even the world, instantaneously. Funds can be transferred with a key stroke from one account to another. A buyer can visually examine a product thousands of miles away, purchase and receive it without getting up from his couch.
In spite of these technological advances, the US Congress continues to operate in the same fashion that it did over 200 years ago. These elected "public servants" gather, at the tax payers' expense, in a location removed from the personal attention of those they represent, who then must use the new-fangled methods of the 21st century to make their opinions known to these servants. Gathered as they are in one not-so-central location, the senators and representatives form a stationary target for the lobbyists representing the various interests with a stake in impending legislation. Who needs this? A constitutional amendment is required that would change the operating procedure of the US Congress to reflect the advances of two centuries. They belong in the districts that they represent, they can communicate with one another, and vote, with modern techniques.