Howard Dean

DNC Chairman Howard Dean: Getty Images PhotoDemocratic National Committee Chairman Howard Dean will make a three-stop campaign trip in Hershey and Philadelphia on Friday as the latest Barack Obama surrogate to spend time with state voters.

Dean will speak on behalf of the Democratic presidential nominee at the SEIU union Healthcare PA Annual Convention in Hershey Friday morning before heading to Temple University for an afternoon registration rally. His last stop will be in the heart of Philadelphia at a Campaign For Change field office at 1500 Sansom Street.

The trip will be Dean's second to Pennsylvania in as many months. The chairman made a mid-August visit to Harrisburg, calling Pennsylvania a "must-win" for Obama.

Some polls have shown Obama's lead in the Keystone State, once consistently at 5 points or higher, entirely disappeared.

Check back next week to view my Convention Sketchpads from the Republican National Convention in Minneapolis.

The fourth and final day of the Democratic National Convention will be called to order at 5:00 PM EST on Thursday, with a theme of "Change You Can Believe In."

The final day's events will take place at INVESCO Field at Mile High, where over 70,000 people are expected to attend.

Featured speakers will include Colorado Gov. Bill Ritter (D), former Vermont Gov. and Democratic National Committee chairman Howard Dean (D), New Mexico Gov. Bill Richardson (D), U.S. Rep. and U.S. Senate candidate Mark Udall (D-Colo.), Virginia Gov. Tim Kaine (D), former Vice President Al Gore (D) and U.S. Sen. Dick Durbin (D).

U.S. Sen. Barack Obama (D-Ill.), the Democratic presidential nominee, is scheduled to address the convention at 10 p.m. EST.

The full schedule is below.

Democratic National Committee Chairman Howard Dean today called Pennsylvania a "must win" state for U.S. Sen. Barack Obama (D-Ill.).

Dean's comments, reported by The Patriot-News, reflect consensus among Democrats that Obama cannot afford to lose a state that hasn't gone Republican in two decades, especially in what continues to be a close race.

Dean, who briefly ran for president in 2004, made the remark after stumping for Obama in Harrisburg. Thanks to recent changes in voter registration patterns, Democrats in Pennsylvania now outnumber Republicans by about one million voters.

Both Obama and U.S. Sen. John McCain (R-Ariz.) have spent millions of dollars in Pennsylvania so far, though McCain himself has campaigned in the state significantly more often than Obama in recent weeks.