Barack Obama resigned his US Senate seat on a grace note.

Unfortunately, the process of replacing him may not be so graceful as his exit from the chamber in which he has served for the better part of four years.

Obama’s letter to his Illinois constituents, published Sunday in the state’s newspapers, recalled a distant era in American politics when legislators saw themselves as being of a state — and deeply connected to that state’s electorate.

Here is what Obama wrote:

Today, I am ending one journey to begin another. After serving the people of Illinois in the United States Senate — one of the highest honors and privileges of my life — I am stepping down as senator to prepare for the responsibilities I will assume as our nation’s next president. But I will never forget, and will forever be grateful, to the men and women of this great state who made my life in public service possible.

More than two decades ago, I arrived in Illinois as a young man eager to do my part in building a better America. On the South Side of Chicago, I worked with families who had lost jobs and lost hope when the local steel plant closed. It wasn’t easy, but we slowly rebuilt those neighborhoods one block at a time, and in the process I received the best education I ever had. It’s an education that led me to organize a voter registration project in Chicago, stand up for the rights of Illinois families as an attorney and eventually run for the Illinois state Senate.

It was in Springfield, in the heartland of America, where I saw all that is America converge — farmers and teachers, businessmen and laborers, all of them with a story to tell, all of them seeking a seat at the table, all of them clamoring to be heard. It was there that I learned to disagree without being disagreeable; to seek compromise while holding fast to those principles that can never be compromised, and to always assume the best in people instead of the worst. Later, when I made the decision to run for the United States Senate, the core decency and generosity of the American people is exactly what I saw as I traveled across our great state — from Chicago to Cairo; from Decatur to Quincy.

I still remember the young woman in East St. Louis who had the grades, the drive and the will but not the money to go to college. I remember the young men and women I met at VFW halls across the state who serve our nation bravely in Iraq and Afghanistan. And I will never forget the workers in Galesburg who faced the closing of a plant they had given their lives to, who wondered how they would provide health care to their sick children with no job and little savings.

Stories like these are why I came to Illinois all those years ago, and they will stay with me when I go to the White House in January. The challenges we face as a nation are now more numerous and difficult than when I first arrived in Chicago, but I have no doubt that we can meet them. For throughout my years in Illinois, I have heard hope as often as I have heard heartache. Where I have seen struggle, I have seen great strength. And in a state as broad and diverse in background and belief as any in our nation, I have found a spirit of unity and purpose that can steer us through the most troubled waters.

It was long ago that another son of Illinois left for Washington. A greater man who spoke to a nation far more divided, Abraham Lincoln, said of his home, “To this place, and the kindness of these people, I owe everything.” Today, I feel the same, and like Lincoln, I ask for your support, your prayers, and for us to “confidently hope that all will yet be well.”

With your help, along with the service and sacrifice of Americans across the nation who are hungry for change and ready to bring it about, I have faith that all will in fact be well. And it is with that faith, and the high hopes I have for the enduring power of the American idea, that I offer the people of my beloved home a very affectionate thanks.

With that letter, Obama departed the Senate. In doing so, he left a vacancy that could well be filled by a legislator as impressive as the president-elect. The apparent frontrunners for the seat, Congressman Jesse Jackson Jr. and Congresswoman Jan Schakowsky are leading progressive members of the House. Both have more experience than the man they seek to replace, and both would bring the proper perspectives to the Senate: supportive of Obama but not rubber-stamps, populist in their approaches to trade and economic debates, distrustful of military adventurism and committed to the Constitution. (Needless to say, both would be dramatically better picks than some of the other potential successors, such as Rahm Emanuel acolyte Tammy Duckworth.)

But, unlike Obama, neither Jackson nor Schakowsky, nor any of the other prospects for the seat, will face the voters of Illinois.

That’s because Illinois’ open Senate seat will not be filled by the people of Illinois. It will be filled by a single individual: Governor Rod Blagojevich.

Blagojevich is, like Obama, Jackson and Schakowsky, a Democrat. But he is an extremely controversial Democrat, whose administration has been rocked by ethics scandals. He is, as well, an edgy political player who some fear will make the appointment with an eye toward serving his own interests rather than those of the state or nation.

That’s the problem with allowing governors to appoint senators.

When the Constitution was changed in 1913 to require the election of senators, a loophole was left for circumstances when seats go vacant an elected senator’s term is ended. States were allowed to decide how the vacancies would be filled. Only a handful of states — Wisconsin, Oregon and Alaska — require special elections to fill Senate vacancies. A few more allow for special elections in some circumstances. But the vast majority place the entire responsibility for filling a Senate seat in the hands of a governor.

This is an anti-democratic model for choosing senators. In fact, it is worse than the pre-1913 system of allowing state legislatures to do the picking.

Unfortunately, Illinois is not about to change its rules at this point.

So Obama’s successor will sit as an unelected senator, as did the successors to former Senate Majority Leader Trent Lott and former Wyoming Senator Craig Thomas during the last Congress.

The selection process can be made more responsible than in most states, however. How so?

The Illinois chapter of Progressive Democrats of America has proposed taking steps to open up the process:

As we celebrate President-elect Barack Obama’s electoral victory, and glory in the democratic process that sends him to the White House, we must also be mindful of the very undemocratic process likely to unfold for selecting his successor in the US Senate.

Because this seat will be up for election in less than two years, the Illinois Constitution calls for you as Governor to appoint the replacement for Senator Obama. At the same time we will see special elections to replace our representatives in the House, like Rahm Emmanuel. This is a throwback to the time when State Legislatures chose the Senator and only the House was by popular vote. The times have changed and we strongly feel that it is critical that you allow some form of democratic feedback to the process.

The new Senator will serve out President-elect Obama’s term till 2010, and then run in a state-wide election. By then, the “named person” will enjoy the incumbent’s advantage and likely remain in the Senate for years to come. So, now is the time for you, our governor–though not legally bound to do so–to open this process to allow for real input from the people of Illinois and do so in part to honor the wonderful example of faith in the electorate set by our next President, Barack Obama.

We call on you, Governor Blagojevich to devise a more democratic process that seeks input from communities around the state, by holding open forums to allow the people of Illinois to weigh in on this most important position. Please take into account the consensus of the people as you move forward. Just as the people of Illinois selected Barack Obama and you, Governor to be their leaders, so should they have appropriate input in choosing our next United States Senator.

Ultimately, the United States needs a constitutional amendment to require that all Senate vacancies that occur during the first five years of a senator’s term be filled by special elections. No senator should be allowed to sit for a full session of Congress as an unelected legislator.

But, until that happens, the best way to honor Obama’s service is to assure that the process of replacing him in the Senate is as democratic, open and transparent as possible.