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Tradition dictates that presumptive GOP nominee Mitt Romney will wait until the end of August, right before his party’s convention, to announce his choice of running mate. But the candidate is reportedly exploring the idea of announcing the vice presidential pick in time to boost fundraising during the August lull.

And although Romney pays the usual deference to choosing someone who can lead the country in the president’s absence, a veep choice who can help him raise campaign cash has taken on heightened importance in a presidential election in which spending is expected to exceed $1 billion.

A few of the contenders on the short list are proven money magnets. There’s John Thune of South Dakota, who raised $12.5 million during his 2010 Senate race despite being unopposed, and his young colleague, Marco Rubio of Florida, who brought in an impressive $22 million for his first Senate race the same year. In the House, Wisconsin Rep. Paul Ryan has leveraged his position as House Budget Committee chairman to become a prolific fundraiser in the last four years, vastly exceeding his House colleagues’ averages and raising over $4 million through his leadership PAC.

Virginia Gov. Bob McDonnell helped lead the Republican Governors Association to a $44 million haul in 2011, more than double the association’s take four years ago, when it had a comparable number of races to underwrite. New Jersey Gov. Chris Christie, who won his 2009 race despite being outspent roughly 5-to-1 by Democrat Jon Corzine, has since rebounded and helped raise more than $9 million for candidates across the country. And to the south, Louisiana Gov. Bobby Jindal nearly doubled the haul of his 2007 opponent, Democrat Walter Boasso.

Most of these potential running mates are popular in their home states or districts and have loyal networks of supporters, one pattern of strong fundraisers, said Center for Responsive Politics senior fellow Bob Biersack. Others, like Rubio, have developed national constituencies and attract a high percentage of smaller, individual contributions.

“It’s a lot of hard work,” said Fred Malek, who was Republican presidential candidate John McCain’s 2008 national finance co-chair. “You’ve got to keep your enthusiasm up through many, many events and you’ve got to have the endurance to go through many events.”

Here’s a look at the fundraising chops of some of the leading candidates:

Ohio Sen. Rob Portman: Portman blew his Democratic opponent, Lee Irwin Fisher, out of the water during his 2010 Senate race. Sure, as a former House member and executive-level appointee in the George W. Bush administration, Portman had a head start on name recognition, but he still managed to bring in about $10 million more than Fisher, raising $16.5 million. His donations were split nearly evenly between in-state and out-of-state individuals donating more than $200. That includes strong showings of over $500,000 from the swing states of Florida and Virginia and traditional money powerhouse New York.

His national appeal remains strong as the 2011-12 election cycle has already shown tens of thousands of additional dollars coming in from New York and Virginia. His leadership PAC, Promoting Our RepublicanTeam, has already raked in $1.1 million. In addition to sending $21,000 to House members from the Ohio delegation, Portman has donated $95,000 to 13 Senate colleagues and Republican candidates. The PAC also contributed to former Minnesota Gov. Tim Pawlenty’s failed presidential bid, and made a $5,000 contribution to Romney’s campaign.

Conclusion: Portman would bring Romney a sizeable base of big donors from across the geographic spectrum.

South Dakota Sen. John Thune: No challenger in 2010? No matter. Thune brought in a cool $12.5 million for his race. He spent only $5 million of that, leaving him with $7 million in cash on hand, and he has already raised an additional $1.7 million toward his 2016 race. He also has a strong national profile and an established fundraising presence in places like California, Texas, Florida and Virginia, but has also raised more than $100,000 from Midwestern states like Missouri, Illinois, Minnesota and Colorado. His leadership PAC, Heartland Values, was also hard at work from 2005 to 2010, raising $3.3 million. From 2008 to 2010, the PAC gave $221,000 to over 30 Republican senators and candidates around the country. This cycle, Thune’s leadership PAC donated $2,500 to Pawlenty’s campaign and recently made a $1,652 donation to Romney.

Conclusion: Thune’s clearly got a talent for bringing in cash, even in the absence of life-or-death situations, and is a demonstrated team player for his party. He could help Romney in the Midwest, outside of the traditional coastal fundraising strongholds.

Florida Sen. Marco Rubio: Florida is an expensive state to campaign in, as many of the 2012 presidential candidates learned during the primary. But Rubio still brought in an eye-popping $21.7 million in his Senate bid against two challengers, Republican Charlie Crist and Democrat Kendrick Meek. Like Thune, he shows no signs of slowing down, having raised $4.5 million toward his next race. Better yet, 89 percent of Rubio’s contributions during his 2010 Senate race came from individual donors, showing that he commands loyalty from a large base of supporters. That base was mostly inside Florida, 2010, which was home to 62 percent of his individual donations over $200 during 2010. But his national presence is growing, and while he still does best in Florida, he brings in some serious cash in California, Texas and New York. His leadership PAC, Reclaim America, which he launched in 2010, has raised just over $1 million, but as of the most recent reporting deadline, June 4, it had made just $5,000 in disbursements.

Conclusion: Rubio’s fundraising potential is huge, and his network in a key swing state is formidable. He could help Romney attract more individual, small-dollar donations.

Rep. Paul Ryan of Wisconsin: Ryan is a young star in his party and he has the money to show it. While the average House Republican has raised $463,508 for the 2012 congressional elections, Ryan has amassed $3.2 million. In 2010, he raised nearly $4 million. His leadership Prosperity PAC brought in $1.1 million in the last cycle, and $3.4 million so far in this cycle. In addition to making sizeable donations to his colleagues ($556,500 to fellow House Republicans in the 2010 election), he gave $30,000 to the National Republican Campaign Committee in 2010, and $30,000 to the Republican National Committee in 2012. Ryan’s out-of-state donors have increased every year, especially in the key states of California, Florida, Virginia and New York. Ryan is also another strong Midwestern fundraiser, with nearly $200,000 in individual contributions over $200 originating in Illinois this cycle.

Conclusion: Ryan is a standout fundraiser in the House, establishing geographic diversity in his contributions and demonstrating he is willing to help maintain the financial health of the party.

Virginia Gov. Bob McDonnell: During the last election cycle, he raised the most money of any of the politicians listed here, bringing in $24 million for his 2009 race. That number bested Democratic challenger Creigh Deeds by $7 million and exceeded the fundraising success for former governors Tim Kaine and Mark Warner, both Democrats. About 37 percent of his contributions came from out of state. He was also a favorite of conservative policy organizations, which donated about $2.1 million to his race.

As the head of the Republican Governors Association, McDonnell has increased his national exposure. He assumed the chairmanship after Texas Gov. Rick Perry departed for a presidential bid in August 2011. Between January 2011 and the end of the first quarter of 2012, the group raised more than $56 million, twice the total as the Democratic Governors Association. “He’s a conservative who wears well on the boardroom. You have strong conservative credentials but he has the respect of the business community,” said RGA Executive Director Phil Cox, who also McDonnell’s 2009 campaign. Asked whether McDonnell enjoys the fundraising process, Cox said, "'Enjoy' might be a strong word for it, but he’s a competitor. If you give him a number, he wants to exceed it. He’s competitive and likes to win.”

Conclusion: Already a powerhouse fundraiser, McDonnell has increased his national reach with his RGA role. He seems to embrace the unpleasant task of raising money, a plus for Romney.

Louisiana Gov. Bobby Jindal: In the past, candidates for governor of Louisiana have raised about $5 million. Jindal raised $13.8 million for his 2007 bid against Democrat Walter Boasso, who raised $7 million. Over the next four years, Jindal raised $15.2 million ahead of his 2011 reelection race. His out-of-state donations increased between his two gubernatorial elections, from 11 percent in 2007 to 30 percent in 2011. Especially lucrative for him has been neighboring Texas, where he raised $2 million over the course of his career. He’s also done well in the important fundraising states of California, Florida and New York, and his Gulf Coast roots have helped him secure $662,000 from the oil and gas industry. Jindal is currently serving on the executivecommittee of the RGA, which has helped expand his national profile.

Conclusion: Jindal could help Romney shore up giving from Southern states, where he is a popular commodity. He’s also proven he will go above and beyond the necessary fundraising.

New Jersey Gov. Chris Christie: Christie’s 2009 opponent, Democrat Jon Corzine, swamped him in the money department – Corzine raised $30.6 million to Christie’s $5.8. At the time, 83 percent of his donations came from within New Jersey. Since then, his fundraising star has taken off. Christie is serving as the vice chairman of the RGA, meaning he has helped McDonnell bring in the group’s impressive haul and is getting exposure to big Republican donors across the country. He has also become an in-demand fundraising partner for other Republican candidates. In 2010, he helped raise $9 million for candidates in 15 states, according to his 2009 strategist and longtime advisor Mike DuHaime.  Since 2011, Christie campaigned or raised money for Romney in six states, and visited Wisconsin, Iowa, Missouri, North Carolina, New York, Massachusetts, Indiana, Ohio, Virginia and Kentucky to help other federal candidates raise money. Those trips have likely brought in about another $4 million nationally.

Conclusion: Christie has strong roots in the New York fundraising world, and he is an effective team player for the national party.

This article is from the archive of our partner The Wire.

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