It will be a while before we know if presidential candidate Mitt Romney's pick of Rep. Paul Ryan to join the Republican ticket will be a plus or minus for his campaign.

In my view, not since Jack Kennedy picked Lyndon Johnson has the choice of a running mate truly affected the outcome in November. LBJ did, after all, help bring Texas to the Democratic fold in 1960. But the record for subsequent No. 2s is a bit mixed. Here's my scorecard:


Democrat: President Lyndon Johnson, without a vice president since he succeeded the assassinated John F. Kennedy in 1963, named Hubert Humphrey, the Senate majority whip, at the convention. He said the Minnesotan was best qualified to become president should something happen to him. Humphrey's avowed liberalism also helped soften some opposition to Johnson from the left. Verdict: PLUS.


Sen. Barry Goldwater picked Rep. William Miller of New York, the head of the National Republican Congressional Committee. Miller had already announced his decision to retire in '64, but as an Easterner and Roman Catholic, he would bring geographical and religious balance to the GOP ticket. Or, as Goldwater said on more than one occasion, he picked Miller because "he drove LBJ nuts." Ultimately, though, Miller was a nonfactor in the election, in which the GOP was buried in November. In fairness, nothing was going to help Goldwater that year. Verdict: MINUS.


Republican: It's not clear whether Richard Nixon even met Spiro Agnew before choosing him as his running mate. Agnew, elected governor of Maryland in 1966 as a liberal, moved steadily to the right in 1968, especially since Agnew's original choice for the White House, New York's Nelson Rockefeller, dillydallied on deciding whether to run. Agnew also received national attention when he directly criticized black leaders in Maryland in the wake of the riots following the assassination of the Rev. Martin Luther King Jr. That apparently won the notice of Sens. Strom Thurmond, R-S.C., and John Tower, R-Texas, who urged Nixon to go with Agnew — which he did, one day after Agnew nominated him for president at the convention. Of course, this was in the day when vetting potential VP picks was unheard of; had anyone done the most cursory investigation of Agnew, they might have learned about his corruption and bribe-taking — an activity that began even before his governorship, when he was Baltimore County executive. But Agnew did provide the red-meat attack-dog rhetoric Nixon clearly sought in his running mate. Verdict: MINUS.

Democrat: Sen. Ed Muskie of Maine may have been just as much of a national political unknown as Agnew was, but he was considered a serious and thoughtful, if colorless, legislator. And while presidential nominee Hubert Humphrey took a pounding, mostly from the left, during that divisive general election campaign, Muskie won respect from both wings of the party throughout the fall. Verdict: PLUS.


Democrat: If no running mate was going to help Barry Goldwater in 1964, the same could be said about whomever George McGovern was going to select in 1972. Still, the revelation by Sen. Thomas Eagleton of Missouri — just two weeks after he was picked — that he had been treated for depression with electroshock therapy and was hospitalized several times in the early 1960s threw the party for a loop. McGovern may have famously said he was "1,000 percent" for Eagleton, but there was tremendous pressure on Eagleton to withdraw ... which he did, 17 days after being named to the ticket. Verdict: MINUS.

The Democratic National Committee then named Sargent Shriver as Eagleton's replacement, but he was a nonfactor for the rest of the campaign. McGovern had tried to entice other Democrats onto the ticket, including Sen. Edward Kennedy, but they all said no. Verdict: MINUS.


Democrat: If Jimmy Carter was an outsider from the South with anti-establishment credentials and no Washington experience, Sen. Walter Mondale of Minnesota, a big-government liberal and a member of the "club" in good standing, was the perfect counterbalance. Though Carter was to have a strained relationship with many Democrats in Congress, they never lost their respect for Mondale. He also was a clear winner in his VP debate against Kansas Sen. Bob Dole. Verdict: PLUS.

Republican: In choosing Bob Dole as his running mate (and dumping Vice President Nelson Rockefeller in the process), President Gerald Ford did not focus on geographical or ideological balance. He was looking for a take-no-prisoners conservative battler who would appeal to the supporters of defeated presidential hopeful Ronald Reagan. But Dole proved to be a testy campaigner, and his performance in his debate with Mondale was seen as a disaster, notably his description of the two World Wars, Korea and Vietnam as "Democrat wars." Verdict: MINUS.


Republican: Ronald Reagan may have campaigned as a steadfast conservative, but in choosing George H.W. Bush as his running mate, he showed his pragmatic side. Bush was a conservative but in the moderate mode, and the Reagan-Bush ticket unified the party. Bush, of course, had to take back his earlier criticism of Reagan's economic policies and abortion views. It was the first time a GOP ticket was made up of rivals for the nomination since 1944, when New York Gov. Thomas Dewey chose John Bricker, his counterpart from Ohio. Verdict: PLUS.


Democrat: Walter Mondale may have thrown a Hail Mary pass with his selection of Rep. Geraldine Ferraro of New York as his running mate, the first woman in history to appear on a major-party ticket. But the history of the moment, and the ecstatic response the choice received from feminist groups, soon gave way to troubling news about the financial affairs of Ferraro's husband. In the end, though, no one can claim that the distraction about John Zaccaro is what did in Mondale — who lost 49 out of 50 states to President Reagan. But a distraction it was. Verdict: MINUS.


Republican: On paper, Vice President George Bush's argument for selecting Sen. Dan Quayle of Indiana made sense. He was young, but not Jack Kemp; he was from the Midwest, where Bush needed help, but not Bob Dole. And he had the reputation of being a giant killer, having toppled Democratic Sen. Birch Bayh in 1980. But just as Ferraro's family finances were not properly vetted by the Dems in '84, the process by which Quayle joined the National Guard in the middle of the Vietnam War, and the family connections he used to get him there, became the story from Day One. And his performance against Democratic VP pick Lloyd Bentsen in their debate has forever been described as a "deer in the headlight" moment for Quayle. With the Bush-Quayle ticket winning 40 out of 50 states in November, it became one of the instances in which a ticket won despite the VP candidate. Verdict: MINUS.

Democrat: Since the Boston-Austin axis worked so well for Kennedy and Johnson in 1960, there was no reason for Massachusetts Gov. Michael Dukakis to think it wouldn't work again when he picked Texas Sen. Lloyd Bentsen. And although Bentsen won plaudits with his handling of GOP rival Dan Quayle during his famous "You're no Jack Kennedy" debate performance, some in the party felt that Bentsen was a wrong fit from the beginning: He differed from Dukakis on many issues, and he was too far to the right for many progressives in the party to accept. And, unlike the 1960 comparison, Bentsen failed to bring along his home state of Texas. Many Republicans suggested that before Dukakis debated Vice President Bush, he might have to settle his differences with Bentsen. Verdict: MINUS.


Democrat: Bill Clinton abandoned conventional wisdom when he selected Sen. Al Gore as his running mate. Rather than seek any kind of geographical, ideological or demographic balance, the Arkansas governor instead picked someone very similar to himself: a young moderate from nearby Tennessee. One way they differed: While Clinton had the reputation of being a draft-dodging womanizer, Gore served in Vietnam, and his wife was a vocal promoter of "family values." And that didn't hurt either. Verdict: PLUS.


Republican: Plain and simple, Bob Dole selected, in Jack Kemp, someone he didn't agree with or especially like. They ran against each other for the nomination in 1988 and were on opposite sides of the deficit reduction vs. supply-side economics debate. But Dole, running behind President Clinton all year, decided that he needed to go for broke, and Kemp, though out of office eight years, remained popular with the Reagan wing of the party. Kemp, however, distinguished himself neither on the campaign trail nor in his debate with Vice President Gore. Verdict: MINUS.


Republican: Dick Cheney, who headed up George W. Bush's search committee for a running mate, perhaps knew better than anyone what the Texas governor lacked: national security and foreign policy experience. And he provided it. As someone who never pined for the White House, Cheney's addition was more about governing than simply campaigning. We can argue whether his policy pushes during his eight years in office were popular or not, but no vice president played a more crucial role in determining the course of the nation than Cheney. Verdict: PLUS.

Democrat: Al Gore was tormented by how to deal with a term-limited President Bill Clinton in 2000. The incumbent remained very popular, but Gore — searching for swing voters who may have been put off by Clinton's personal conduct — seemed determined to make a statement. He named Sen. Joseph Lieberman of Connecticut, the first Jew to run on a major-party ticket — but more important, someone who had publicly and forcefully denounced Clinton's conduct in the aftermath of l'affaire Lewinsky. But if he also picked Lieberman to be an attack dog, he was sorely mistaken. Lieberman went out of his way to be nice, including during his debate with Cheney. And there's no telling how many voters who felt Clinton was a net positive for the party were alienated by Lieberman's selection. Verdict: MINUS.


Democrat: To say that John Edwards was not a successful vote-getter during the Democratic primaries would be an understatement; he won only one state, South Carolina, where he was born. But he had a winning campaign style, and presidential nominee John Kerry, despite some personal misgivings, picked him to fill the ticket. Still, Edwards failed to bring in any Southern state in November to the Democratic column, and many partisans felt he was insufficiently aggressive in his debate against Vice President Cheney. And this negative report card does not include his later indefensible behavior in his personal life. Verdict: MINUS.


Democrat: In his two tries for his party's presidential nomination, Sen. Joe Biden of Delaware never got very far. He could be, and was, long-winded and vain. He had a habit of making embarrassing gaffes, and several of his comments about Barack Obama ("articulate" and "clean," that the White House was not the place for "on the job training") threatened to come back and haunt him. If Obama was making the case that he opposed the war in Iraq from the beginning and stood for genuine change, he was naming a running mate who was 65, had been in the Senate since 1973 and voted for the war. But Biden was a great campaigner, very smart and well-liked. And just as Cheney gave the GOP ticket foreign policy bona fides, Biden's vast Washington experience and expertise in foreign affairs helped balance Obama's 15 minutes in the Senate. Verdict: PLUS.

Republican: At the GOP convention in St. Paul, Alaska Gov. Sarah Palin gave a speech that brought the house down. And in doing so, she helped make conservatives who never fully warmed up to John McCain suddenly get enthused and excited about the ticket. That enthusiasm, and Palin's positive reviews, didn't last long. Verdict: MINUS.

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