DENVER -- When Barack Obama and Joe Biden campaign by bus in Michigan, Pennsylvania and Ohio after wrapping up the Democratic National Convention, they'll be following a familiar route.

Republicans George Bush and Dick Cheney took a whistlestop tour by train of Ohio, Michigan and Illinois after leaving their national convention in 2000. And Democrats Bill Clinton and Al Gore launched a 1,000-mile post-convention bus tour in 1992 that took them to New Jersey, Pennsylvania, West Virginia, Ohio, Kentucky, Indiana, Illinois and Missouri.

The point of these trips is to build momentum in battleground states after the conventions.

Obama and Biden, senators from Illinois and Delaware, will be accompanied by their wives, Michelle Obama and Jill Biden.

The pair hope to build support in the three critical industrial states and take away some of the attention focused on Republicans as they gather in Minneapolis-St. Paul to nominate their candidate, John McCain, and his yet-unnamed running mate.

In 2000, Bush concentrated his first post-convention campaign trip on states carried by Clinton and Gore in 1992 and 1996. Bush managed to pry away Ohio in both 2000 and 2004.

This time, Obama and Biden hope to hold onto Pennsylvania and Michigan and regain Ohio in their November contest against McCain, and the trip is their first post-convention chance to work on that.