HERE IS a do-it-yourself scorecard to select a running mate for John McCain.
On the following 20 criteria, rate possible vice presidential candidates from 1 (poor) to 5 (excellent). Add those 20 numbers and - presto! - you'll have your top-scoring finalists.
If a candidate rated a 5 on each of the 20 criteria, the total score would be 100. But no one is perfect.
For each criterion, you'll see a sample candidate who deserves a high-5 score. At the end, you'll see my ranking of 20 candidates who have been speculated about as realistic prospects.
Woman or minority
A female, African-American, or Hispanic nominee could cut into the Democratic vote.
Example of a high-5 score: Condoleezza Rice, secretary of state, female, African-American, fluent in four languages.
Middle-age and healthy
The optimum age is between Barack Obama's age, 46, (younger would imply that youth has greater value than experience) and 59 (older would allow critics to caricature the ticket as two old codgers). Candidate should be in excellent health.
Example of a high-5 score: Senator Sam Brownback of Kansas, age 51.
The best candidates have already been vetted and have a reputation for integrity.
Example: Chris Cox, chairman of the Securities and Exchange Commission, former California congressman.
The nominee should be popular with conservatives, but not viewed as radically conservative by swing voters.
Example: Minnesota Governor Tim Pawlenty.
Can carry swing state
A candidate who's popular in a key state could provide the margin of victory there.
Example: Florida Governor Charlie Crist.
Record of results
A candidate should have achieved major policy changes that benefited the public.
Example: former New York mayor Rudy Giuliani.
For a balanced ticket, legislator McCain should pick a governor or administrator.
Example: Tom Ridge, former secretary of homeland security, former Pennsylvania governor.
The candidate should have fiscal or business experience to bolster McCain's credibility on economic issues.
Example: Rob Portman, former director of Office of Management and Budget, former Ohio congressman.
Ideally, the nominee would be someone McCain considers a true friend and ally.
Example: Senator Lindsey Graham of South Carolina.
A vice presidential candidate often needs to be aggressive in criticizing the opposition.
Example: Mississippi Governor Haley Barbour, former national GOP chairman.
The nominee needs to out-debate the Democratic VP candidate, using compelling arguments, anecdotes, and humor.
Example: former Arkansas Governor Mike Huckabee.
The candidate needs to be persuasive, quotable, and calm under pressure.
Example: US Representative Mike Pence of Indiana, former radio and TV talk show host.
A vice president should help win congressional support for the president's agenda.
Example: House Republican leader John Boehner of Ohio.
Voters naturally prefer candidates who are personable and appealing.
Example: US Senator John Thune of South Dakota.
Secure the South
Some Southern states that have been reliably Republican could be at risk if Obama is the Democratic nominee. A candidate popular in the South would help maintain the base.
Example: South Carolina Governor Mark Sanford.
Vice presidents can help heal party wounds, and they are often sent overseas for state ceremonies and coalition-building.
Example: US Senator Elizabeth Dole of North Carolina, served five presidents, former president of the Red Cross.
Nominees are partly judged by their family life.
Example: Former Massachusetts governor Mitt Romney, happily married and proud father of five sons.
Expanding the GOP
An enthusiastic vice president can help reinvigorate the party and attract new people.
Example: John Kasich, former Ohio congressman, Fox TV host.
Candidates should be able to win tough contests without losing their likability.
Example: Kay Bailey Hutchison, US senator from Texas.
Prepared to be president
"Ready from day one" is the most important criterion for many voters.
Example: Colin Powell, former secretary of state, past chairman of the Joint Chiefs of Staff.
HERE'S MY RANKING of the 20 candidates - from weakest to strongest.
BOTTOM 10: Haley Barbour 55, Mike Pence 57, John Boehner 60, Mitt Romney 62, Rudy Giuliani 63, John Thune 64, John Kasich 65, Rob Portman 66, Lindsey Graham 67, Tom Ridge 68.
TOP 10: Mark Sanford 70, Elizabeth Dole 71, Sam Brownback 73, Chris Cox 75, Kay Bailey Hutchison 76, Colin Powell 78, Mike Huckabee 79, Condoleezza Rice 80, Charlie Crist 81, Tim Pawlenty 85.
McCain's VP search committee has yet to set its own criteria for screening candidates, so don't order your McCain-Pawlenty bumper sticker yet.
Meanwhile, Pawlenty might find comfort and hope in what McCain said about him during the 2006 campaign: "This is the kind of leadership that I'd like to pass the torch to."
Todd Domke is a Boston area Republican political analyst, public relations strategist, and author.