How close is the race between Senator Barack Obama and Senator Hillary Clinton among Democrats in the increasingly divided Democratic party? It remains a virtual tie…a stalemate…where one slip by one candidate could change the high-stakes dynamics of a race being closely watched by convention superdelegates.

Just look at the latest Gallup Daily tracking poll:

Gallup Poll Daily tracking conducted April 25-27 shows Democrats closely divided in their nomination preferences, with 47% favoring Barack Obama and 46% backing Hillary Clinton.
The race has been stable at a virtual dead heat in each of the last four Gallup Poll Daily tracking reports. This follows Clinton’s victory in the April 22 Pennsylvania Democratic primary — an event which has helped Clinton challenge what had been a growing sense of inevitability around Obama winning the nomination. (To view the complete trend since Jan. 3, 2008, click here.)

Also, the two have been roughly tied in each individual day of polling included in today’s three-day rolling average. Barring any political firestorms along the lines of the recent Rev. Jeremiah Wright and Kosovo controversies, the race could very well remain closely contested through at least the May 6 Indiana and North Carolina primaries.

There is also no change in national registered voter preferences for the fall, with Clinton beating John McCain by three percentage points, 47% to 44%, and Obama running even with McCain, each at 45%.

But there are other polls that provide other glimpses into the evolving preferences of the Democratic and general electorate:

1. A new Rasmussen Reports poll indicates the number of Democrats that want Clinton out of the race is increasing:

Thirty-four percent (34%) of Democrats nationwide now believe that Hillary Clinton should drop out of the race for the White House. That’s up from 32% earlier in April and 22% in late March.

As for Barack Obama, just 22% of Democrats say he should drop out. That’s down from 26% earlier in April and unchanged from 22% in March. Just 1% want both candidates to drop out and 45% aren’t ready for either to leave.

Nationally, Obama holds a modest but steady lead over Clinton in the Rasmussen Reports daily Presidential Tracking Poll.

By a 62% to 25% mark, Obama supporters say that Clinton should leave the race. But, just 4% of those who support Senator Clinton agree. Clinton supporters are evenly divided as to whether Obama should drop out.

Overall, 58% of all voters now believe Obama will be the nominee. That’s down slightly from 62% earlier in the month. Among Democrats 59% expect Obama to win (down from 63%). Rasmussen Markets currently suggests that Obama has an 79.6% chance of winning the nomination.

2. A new Associated Press-Ipsos poll shows Clinton would have an easier time deafeating presumptive Republican nominee Senator John McCain:

Hillary Rodham Clinton now leads John McCain by 9 points in a head-to-head presidential matchup, according to an Associated Press-Ipsos poll that bolsters her argument that she is more electable than Democratic rival Barack Obama.

Obama and Republican McCain are running about even.

The survey released Monday gives the New York senator and former first lady a fresh talking point as she works to raise much-needed campaign cash and persuade pivotal undecided superdelegates to side with her in the drawn-out Democratic primary fight.

Helped by independents, young people and seniors, Clinton gained ground this month in a hypothetical match with Sen. McCain, the GOP nominee-in-waiting. She now leads McCain, 50 percent to 41 percent, while Obama remains virtually tied with McCain, 46 percent to 44 percent.

Both Democrats were roughly even with McCain in the previous poll about three weeks ago.

Since then, Clinton won the Pennsylvania primary, raising questions anew about whether Obama can attract broad swaths of voters needed to triumph in such big states come the fall when the Democratic nominee will go up against McCain. At the same time, Obama was thrown on the defensive by his comment that residents of small-town America were bitter. The Illinois senator also continued to deal with the controversial remarks of his longtime Chicago pastor, the Rev. Jeremiah Wright.

And two pollsters (D&R) agree: these numbers bode well for Clinton:

“I don’t think there’s any question that over the last three weeks her stature has improved,” said Harrison Hickman, a Democratic pollster unaligned in the primary. He attributed Clinton’s gains to people moving from the “infatuation stage” of choosing the candidate they like the most to a “decision-making stage” where they determine who would make the best president.

Added Steve Lombardo, a GOP pollster: “This just reinforces the sentiment that a lot of Republican strategists are having right now — that Clinton might actually be the more formidable fall candidate for a lot of reasons, not the least of which is that Obama can’t seem to get his footing back.”

Note again that polls are see-saws that seemingly fluctuate with the conventional wisdom and with whatever candidate comes out better in a given news cycle. But the bottom line is: they show a serious erosion for Obama and a rebound for Clinton.