WASHINGTON (CNN) -- With both Florida and Michigan primary re-vote plans stalled, the road ahead for Sen. Hillary Clinton appears to be a rocky one.
Sen. Hillary Clinton lags behind Sen. Barack Obama in the popular vote and in pledged delegates.
Sen. Barack Obama leads Clinton in both pledged delegates and popular votes. The question now: Can Clinton overtake Obama's lead in pledged delegates?
For that to happen, she would need to win about two-thirds of the pledged delegates in the remaining contests, which will be tough.
CNN estimates that Obama has 1,413 pledged delegates and 208 superdelegates for a total of 1,621. Clinton has 1,242 pledged delegates and 237 superdelegates, a total of 1,479. A candidate must have 2,024 delegates to win the Democratic nomination.
Another question that arises: Can she overtake Obama's lead in popular votes?
In the primaries and caucuses to date, Obama has garnered about 700,000 more popular votes than Clinton.
CNN estimates that about 6 million more people are likely to vote. To overcome Obama's lead, Clinton would have to get 56 percent of those votes.
So how tough will that be? In the 28 primaries in February and March, when the Democratic contest became a two-candidate race, Clinton averaged 46 percent.
She's received 56 percent or more in only four states: Massachusetts, Rhode Island and her current and former home states, New York and Arkansas.
The next state to vote is Pennsylvania on April 22, where CNN's poll of polls shows Clinton leading Obama by 13 percentage points. If you look only at decided voters, Clinton gets just over 56 percent.
West Virginia and Kentucky are heavily rural states with many lower-income voters, which could be good for Clinton, who has done well with similar voters in Ohio and Texas.
Indiana appears to be more of a battleground. Many Indiana voters get their information from media out of Chicago, in Obama's home state of Illinois. The state holds its primary May 6.
North Carolina, with its large African-American population and swath of upscale voters, is Obama's most promising state. Its primary also is May 6.
Obama may also do well in Oregon's May 20 primary. The Illinois senator has generally done well in Western states where the traditional Democratic base is small.
If Michigan and Florida were to redo their primaries, Clinton would need to carry 53 percent of the remaining voters.
But even that won't be easy. She's gotten at least 53 percent of the vote in only eight of the 28 primaries since Super Tuesday.
The Clinton campaign has pushed for the votes in Florida and Michigan to count, which could help her catch up in pledged delegates. But Obama wasn't on the ballot in Michigan, and both sides agreed not to campaign in the two states.
On Thursday, Michigan's Senate adjourned without reaching an agreement to schedule a new Democratic primary for June 3.
The Legislature is on recess for two weeks, and by the time lawmakers return, it will probably be too late to approve and organize a new vote.
Clinton and Obama also would have to sign off on the plan. Obama's camp had expressed concern with the proposal, and Clinton blamed him for holding up the re-vote.
Michigan and Florida held primaries in January, but the Democratic National Committee stripped them of their delegates for scheduling their contests too early.
The ultimate decision now could very well rest with the superdelegates: the 800 or so Democratic elected officials, party leaders and other officials.
But the superdelegates are likely to pay a lot of attention to who's ahead in the popular vote and in pledged delegates, a fact that could ultimately help Obama surge to winning the party's nomination. E-mail to a friend