Hillary Clinton is seeking to slow rival Barack Obama's momentum ahead of three more contests in the race for the Democratic nomination for US president.
Polls give Mr Obama a slight lead going into bi-party primaries in Maryland, Virginia and the District of Columbia.
Mr Obama won in Washington state, Louisiana, Nebraska, Maine and the US Virgin Islands at the weekend, keeping him neck-and-neck with Mrs Clinton.
She appointed a new campaign manager after the weekend's setbacks.
DemocratsRepublicansHillary Clinton
12 states, 1,136 delegates
Arizona, Arkansas, California, Florida, Massachusetts, Michigan, Nevada, New Hampshire, New Jersey, New York, Oklahoma, Tennessee
Barack Obama
19 states, 1,108 delegates
Alabama, Alaska, Colorado, Connecticut, Delaware, Georgia, Idaho, Illinois, Iowa, Kansas, Louisiana, Maine, Minnesota, Missouri, Nebraska, North Dakota, South Carolina, Utah, Washington state
2,025 delegates needed for nomination. Source AP (includes all kinds of delegates)
Q&A: US election delegates
Mike Huckabee
8 states, 234 delegates
Alabama, Arkansas, Georgia, Iowa, Tennessee, West Virginia, Kansas, Louisiana
John McCain
12 states, 719 delegates
New Hampshire, Arizona, California, Connecticut, Delaware, Florida, Illinois, Missouri, New Jersey, New York, Oklahoma, South Carolina, Washington state
Mitt Romney
11 states, 282 delegates
Campaign suspended
Alaska, Colorado, Maine, Massachusetts, Michigan, Minnesota, Montana, Nevada, North Dakota, Wyoming, Utah
1,191 delegates needed for nomination. Source: AP (includes all kinds of delegates) Maggie Williams, who was the New York senator's chief of staff when her husband was serving as US president, will take over from Patti Solis Doyle, who has decided to step down.
Speaking to Chicago television reporters on Monday, Mrs Clinton sought to play down the importance of the move and said Ms Doyle would be staying on as an adviser.
"There really is not a significant change; we've really just got to get more help," Mrs Clinton said.
She and Mr Obama face a long, drawn-out battle after neither was able to deliver a knockout blow in the 22 state contests of Super Tuesday on 5 February.
Each is about half way to winning the 2,025 delegates needed to secure victory at the Democratic Party's national convention in August.
Both candidates have been campaigning hard ahead of Tuesday's so-called Potomac Primary, named after the river that runs through the two states and the nation's capital.
Virginia has 83 delegates up for grabs, while Maryland offers 70 and the District of Columbia has 15.
Presidential backing
On the Republican side, front-runner John McCain will be hoping for a strong result from the Potomac Primary, where polls suggest he has the edge.
Baltimore voters give their views ahead of primary elections in Maryland
In pictures
Although he won primary polling in Washington state on Saturday, correspondents say the Arizona senator still has some work to do to unite his party, as Mike Huckabee won in Kansas and Louisiana.
Mr McCain faces continuing criticisms from leading party members who have questioned his conservative credentials.
However, he picked up the endorsement of evangelical leader and anti-abortion campaigner Gary Bauer on Monday, which may raise his stock with Christian evangelical voters.
It came a day after President George W Bush described him as a "true conservative" in a taped interview.
NEXT CONTESTS
Tuesday: Maryland, Virginia and Washington DC (bi-party)
Role of super-delegates
Q&A: Election delegates
Send us your comments
Mr Huckabee and third-placed Ron Paul have been coming under pressure to step aside for the sake of party unity, but the former said on Saturday he had no intention of pulling out.
Mr McCain has a wide lead with 719 delegates to Mr Huckabee's 234 and Mr Paul's 14.
Mitt Romney, who suspended his campaign last week, still has 298 delegates.
[BBC]
This will go to the wire and am loving every bit of it
Go obama go … I’m dreaming an african-american in white house.Maybe, the spirit of martin Lurther King still lives.
This year, we are painting the White House black!
Barack Obama has seriously impressed me in this running,im starting to have this feeling that for once an africa-american is going to get the nomination for democrats this time around… history is going to be broken uno mwaka mwe!!!
Analyst, I agree. We will paint the white house with black to make it black house.
america will be destroyed by having a black president.More corruption and party cadre attitudes.
It wont happen. White house forever
a girl can not rule america!!!!!! Obama is america’s saviour
Obama=Osama instead of destroying he will assist in building America.
No interest, we are not concern who wins!!!
Clinton my babe,just lay off and keep your for Chelsea.Obama,young man,keep up the good fight.I hope America is no longer a racist place.We really need some change we can believe in!
My general comments on the manner politics are conducted in the USA – a lot of lessons for Zambia. I am particularly tired of the recurrent method employed in Zambia of handpicking the aspiring candidate by sitting head of state in the ruling party. I also want to see real live public debate by the various candidates especially at presidential level. We need to hear it all from these personality rather than ascendancy to power on silver platter. Come 2011, let us the ball game changing for the better.´The media here have a significant role to play. I am tired of waiting in the dark for possible successor in all parties especially the ruling party.
so far, more than expected for Obama, but still tricky! In the “all kinds of delegates”, are the so called super delegates, who will likely cast the deciding votes, in case of no clear winner-as it seems. These are likely to be Democratic insiders, who may be biasd towards Hilary. Unless they listen to the voice of the general vote.Texas and Ohio could also be tricky,likely pro-H. But overall he has done beyond expectation and he is likeable to the people. Ninsamushi fye shika mulya umwaice!
america will never be ruled by a black president.Pse tell me in Africa which country is ruled by a white man.
#14 Miss Mwansa, Maritius has a white president. SA was once ruled by a white boer Botha and De Clerk.
#14, the answer is RSA was ruled by white men
Is it saying something that most of the conservative leaning states such as kansas and nebraska etc are endorsing Obama? Even the Dallas morning news in Bush country endorsed Obama. The strategy seems to be to forestall Hillary Clinton who has a lucid agenda that clearly defines what she wants to do, and favors minority issues.On the other hand Obama merely proclaims the need for change as his agenda.The republicans know that their best bet is an inexperienced Obama in the stretch run. They are so afraid of the 1-2 of Bill and Hillary. Iam afraid that Obama is merely playing spoiler!
It will be good if this Kenyan man Obama, a Luo by tribe, wins but I don’t see him becoming the President of the US. It’s very unlikely that corporate white america will let an African become President of the USA. He could be picked as VP by Hillary if she wins the presidency. I’m sure the Kikuyus in Kenya will be gutted if a person with Luo blood runs a powerful nation as America. I’m not tribalist, I’m just looking at things in the eyes of a typical tribal Kikuyu person. America will become a no go area for Kibaki and his relatives.
Hahaha!
Truth is Corporate America is really freightened of Billary.Obama is seen as the better evil as he espouses some philosophical views shared by Condi Rice, a few of Alan Keys, and very little of the General, Powell.But you are also right that America is not about to hand over the nuclear button to an african, albeit african american. In the final analysis third world countries like Zambia should study and learn some of the important tenets of popular public opinion, participation and governance. That is your homework Mr President and Mama Maureen.
I wouldn’t say much, but one thing i know is that change is inevitable especially when the people want it couse thats what the us citizens want. Loook at what happened in Kenya, People wanted change and unfortunately it was denied resulting in what is happening now.
I really dont believe there are no great men and women in Africa who can run the white house, there are infact a lot. so please let Obama rule becouse he will be an example of what President of African origin can do.its just unfortunate that in most African countries, Corporate governanace is only in books and not practiced.
Obama is both wblack and white. His mother is white. Itis racism to call him black just because he has a black father. now, we embrace him as black since his cousin Dick Chenney and others want him to be on the black side. This is Obama’s time. Macain might be elected snce some white democrats don’t want a black man and blacks don’t want Hillary.
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