Obama, McCain both need abortion issue

Presumptive Republican presidential nominee John McCain has one ace up his sleeve in his bid to woo disgruntled conservative Christians: his unflinching opposition to abortion rights.

His likely Democratic opponent in the November White House election, Barack Obama, firmly supports abortion rights.

Few other big issues cut so clearly across partisan lines in the United States, a point underscored by McCain and Obama's positions on it. And analysts say while both candidates must be careful they may need the issue to stir their party's bases.