Both Hillary Clinton and Barack Obama's campaigns say they expect Obama to win the Maryland primary on Tuesday, and here's why.

Maryland has a sizeable population of well-educated and affluent white voters especially near Washingon, DC. The more wealthy segment of the Democratic party has, so far, backed Obama.

The state is also 30% black, which also generally goes to Barack. An aggregate of recent polls by website RealClearPolitics.com has Obama leading Clinton 55% to 32%.

Maryland's Democratic governor Martin O'Malley and senator Barbara Mikulski have both endorsed Hillary, but both Obama and Clinton supporters either were unaware of the nods or said they had no effect on their decisions.