Why the difference between the Star Tribune's recount figures and those from the Secretary of State's office?

There are different ways to report the tallies. When the recount began, the Secretary of State's office dialed the odometer back to zero and began adding up the ballots from scratch as they were recounted in the state's precincts.

At week's end, Coleman was ahead of Franken by nearly 4,000 votes in the recount as reported on the Secretary of State's website. However, because only 215 votes separated the candidates after initial count, we know that the margin will tighten as the recount continues.

That's why the Star Tribune decided to focus on changes in that 215-vote gap. The newspaper has replaced each precinct's original tally with its recounted vote as it has come in, recalculating the margin accordingly. By our count, the gap was 282 in Coleman's favor going into the weekend.

The secretary of state receives end-of-the-day reports from recount sites and posts the results on its website, www.sos.state.mn.us, at 8 p.m. each day. The Star Tribune then combines those results with the results already published on www.startribune.com.

How are all those challenged ballots factored into the tally you're using?

Challenged ballots -- that is, ballots where the voter's intent has been determined by an election judge but disputed by one of the campaigns -- are not counted in the recount's running tally.

That could skew the ongoing tally somewhat, because the more challenges each sides makes, the more ballots they're likely to be taking away (for now) from their opponent's count -- perhaps creating a perception that they're either winning or gaining ground when that ultimately may not be the case.

The state Canvassing Board will make the final call on the challenged ballots -- which is why it asked the campaigns last week to try to reduce the numbers.

How are challenged ballots different from rejected absentee ballots?

Challenged ballots are ones that have been cast and are part of the recount. Rejected absentee ballots are ones that were turned aside for various reasons before ever being counted.

With challenged ballots, the question is the intent of the voter -- which candidate did they mean to support? The question with rejected absentee ballots is whether election judges turned them down for the right reasons -- say, lapsed registration -- or whether officials made a mistake in rejecting them.

It's important to remember that most challenged ballots wind up going to the candidate first awarded them by the election judge, and that most rejected absentee ballots are in fact correctly rejected. But in a tight election like this one, every vote can make a difference.

Could the U.S. Senate figure into the outcome?

Yes, by the authority vested in it by the U.S. Constitution. Article 1, Section 5 states that the House and Senate may decide whether members have been properly elected and determine disputed elections.

It wouldn't be unprecedented for the Senate to get involved. Sen. Mary Landrieu, D-La., wasn't certified for 10 months after her narrow victory in 1996 while the Republican-led Rules Committee looked into fraud charges by her opponent. (The Senate finally let the results stand).

In 1926, the Senate actually voted to overturn an election; a Democratic lawyer who had lost to a radical Iowa incumbent by about 750 votes filed a challenge with the Senate Committee on Elections and Privileges, and the Senate voted to seat the lawyer.

It seems unlikely that senators would want to appear in any way to be imposing their will on Minnesota voters. But they could if they wanted to, and no court could stop them.

What are the important dates coming up?

The recount must be finished by Friday , and the Canvassing Board will meet Dec. 16 to certify results; it aims to finish that job by Dec. 19, but will take longer if necessary. The winner is supposed to be sworn into office on Jan. 3, but that's assuming there is a clear winner by then.