President-elect Barack Obama has a profound opportunity to change the way business is done in Washington. Tonight’s victory speech was an important first step at reconciling his differences with Republicans and establishing a new approach to governing. But is he sincere? It’s a question that will be answered almost immediately as he assembles a Cabinet and staff and begins to outline his agenda for the first 100 days in office.

Looking back to some of my commentary earlier this year about Obama, I discovered two posts that touched on his post-partisan appeal. Both were written in February at a time when Obama was still an underdog against Hillary Clinton.

• Feb. 3: Obama’s opportunity with the right. In this post, I examine what Republicans find appealing about Obama and how he might adapt his policies to win them over in the general election. Taxes are a good example of how he tried (sometimes using false information) to outflank John McCain by convincing voters that he would lower taxes more than his GOP opponent. How will that translate into policy? And can he keep liberals from overreaching while attracting conservatives to work with him? These are important questions that will be answered early next year.

• Feb. 12: Why I voted for Obama in Virginia’s primary. I admit I incorrectly argued that he’d be an easier opponent for McCain. (Truth is my earlier analysis, in which I cited McCain’s age as a hindrance, actually turned out to be true.) But I also stated unequivocally the positive benefits of an Obama presidency: improving the U.S. image abroad, strengthening the fight against terrorism by forging new alliances, and most importantly, working with conservatives (as he did with Sen. Tom Coburn) to change Washington’s old way of doing business.

After listening to tonight’s victory speech, I’m once again intrigued about what Obama brings to Washington under the mantle of “change.” Don’t get me wrong, I understand the left’s far-reaching agenda and that dark days are ahead for conservatives. And while I certainly hope Obama’s call for unity is sincere, I also recognize the frustration and anger that so many liberals in Washington embody. After eight years out of power, the left will undoubtedly want to exact revenge and move our country in a direction where government trumps freedom.

The big question is how Obama chooses to govern. Does he take the far left’s agenda and impose it on America? For all those McCain supporters who chanted socialism during the campaign, this wouldn’t come as a surprise. But frankly, I don’t see that happening. Instead, I believe Obama will operate under a more Clintonian model. (If rumors about Rahm Emanuel becoming chief of staff are true, this bolsters my argument.)

Tonight’s results aren’t all that different from Bill Clinton’s 1992 and 1996 victories, when he won 370 and 379 electoral votes, respectively. Clinton never managed 50% of the popular vote. When all is said and done, Obama will probably end up with about 51%. That’s hardly a mandate to transform a center-right nation into a snake pit of socialism. For a political environment that heavily favored Democrats, it’s remarkable how close this election actually turned out to be.

Tonight I heard Barack Obama tell me, one of his political opponents, that he would work hard to earn my support. Call me an optimist, but I hope he does bring change to Washington’s partisanship and pettiness — uniting our country in the process. With so many monumental challenges ahead of us — both foreign and domestic — it’s time we moved away from political posturing and toward policy prescriptions.