W.

Jeb Bush's U.S. presidential bid is boiling down to early voting New Hampshire, some associates say, while others envision his protracted battle for the Republican nomination stretching deep into the spring.

Former Florida Gov. Jeb Bush launched a White House bid months in the making with a vow to win the Republican presidential nomination on his own merits and stay true to his beliefs - easier said than done in a crowded primary contest where his conservative credentials will be sharply challenged.

Former U.S. president George H. W. Bush, 90, has been admitted to a Texas hospital suffering shortness of breath, a family spokesman said Dec. 23.

"President Bush was taken by ambulance to the Houston Methodist Hospital as a precaution after experiencing a shortness of breath earlier this evening," his spokesman Jim McGrath said.