As Mitt Romney nears the announcement of his running mate, it seems an opportune time to look at a little-noticed downside to being considered for national office: Governors who dip a toe into national politics may get a bigger profile across the country, but they also risk getting burned by voters back home.

Below are just a few recent examples of governors who have seen their approval ratings tumble amid the glare of the national spotlight. I focused on sitting governors who either ran for the presidency, prepared for a possible presidential bid, got chosen as a vice presidential nominee or found themselves a serious candidate for a vice presidential nomination. I didn't consider governors who looked to higher office only after leaving the statehouse or governors who ran for the U.S. Senate.

With that said, let's get started:

Mitt Romney: A Republican who was able to break 50 percent approval early in his term governing a solidly blue state, Romney finished up with approval ratings in the mid- to high 30s. As The Atlantic recently noted, "By his third year in office, it was apparent Romney's priorities lay elsewhere. He turned against abortion rights and took stands against stem-cell research and gay marriage, and began turning up in states like Iowa, New Hampshire and South Carolina. In those appearances, he frequently made jokes at the expense of his own state as he tried to win favor with conservatives."

Sarah Palin: Palin's star turn after being named the Republican vice presidential nominee in 2008 may have energized the GOP base nationally, but it irritated many voters back home in Alaska. Prior to her nomination, Palin's approval ratings ranged from the 70s to the low 90s. By the time she stepped down from the governorship in 2009, Palin's ratings had settled into the mid-50s. While a lot of governors would kill for ratings that high, Palin's outspoken conservatism and attack-dog role alienated many Alaska Democrats and Independents who had once appreciated her maverick persona. "Some Alaskans turned against what they saw as her newly aggressive, mean-spirited demeanor," the Anchorage Daily News reported in October 2008.

Rick Perry: The Texas governor's short-lived 2012 presidential bid -- best remembered for such gaffes as his inability to remember which cabinet agencies he had proposed eliminating -- "left a sour taste with many Texans and damaged his standing with Republican voters," the Austin American-Statesman concluded shortly after Perry's departure from the race. A survey by the paper found that only 40 percent approved of Perry's performance as governor following his presidential run -- down 10 points from a year earlier, and Perry's lowest approval rating in 10 years worth of polls. A recent Public Policy Polling survey found that just 29 percent of voters in his staunchly Republican state think Perry should run again, and 64 percent don't.

Tim Pawlenty: Though he experienced a decline less severe than that of other governors on this list, Pawlenty -- a Republican who governed a state that tends to vote Democratic in national elections -- also saw his numbers fall as his national profile rose. Toward the end of his two terms, Pawlenty was first a runner-up to Palin as the 2008 vice presidential nominee, and later the focus of speculation -- correct, as it turned out -- that he would run for president in 2012. By March 2010, Pawlenty's approval rating had sunk to a low of 42 percent, about 10 to 15 points below his typical range. "Once the rumors of Pawlenty's national political ambitions really began to take hold in 2009, Pawlenty's approval numbers began to drop and never quite recovered," Eric Ostermeier of the University's Center for the Study of Politics and Governance wrote at the time.

If these examples suggest that this is a recent phenomenon -- or a specifically Republican problem -- it's not. Consider:

Michael Dukakis: A Democrat, Dukakis won the Massachusetts governorship three times before he ran for president in 1988. He won the nomination but lost the general election to George H.W. Bush; after his loss, Dukakis' fortunes as governor went south. Dukakis "left office with much worse numbers" thanks in part to his presidential run, combined with an economic slump, said Fred Bayles, director of Boston University's State House Program. Dukakis "left office under a cloud and remained relatively anonymous for years after," Bayles said. "And he was the last Democratic governor in Massachusetts for 16 years."

Jerry Brown: In 1976, Brown -- then 38 and with only two years under his belt as California's governor -- ran for president. Initially, his youth made him a phenomenon, and the national run didn't hurt him with voters. That changed dramatically when Brown tried again in 1980. Though he'd been handily reelected as governor in 1978, Brown decided to challenge a president (Jimmy Carter) and a revered senator (Ted Kennedy) from his own party; he ended up winning only a single-digit share of the vote in his home-state presidential primary. "Based on the combination of his '76 and '80 runs, the perception clearly set in that Brown wasn't minding the store, was bored with his day job and that his staff was essentially running the state," said Garry South, a veteran Democratic strategist in the state. "Brown left after two terms a disliked and discredited governor. It was driven by a number of things, but in no small part it was his focus on running for president -- unsuccessfully -- twice when he should have been doing the job the voters elected him to do." (Brown, of course, subsequently rebounded and was elected to a third term in 2010.)

To be sure, not every governor suffers this fate. It helps if voters already suspected that you had higher aspirations when they first elected you.

For instance, former Florida Gov. Jeb Bush was a national figure well before winning the governorship, largely because he is a member of a political dynasty. Not only did Bush have a largely successful tenure as governor, but it should have shocked no one that he might one day run for higher office, said Susan MacManus, a University of South Florida political scientist. His brother, Texas governor (and later president) George W. Bush, falls into the same category.

Ronald Reagan, for his part, didn't come from a political family, but his celebrity status helped him become California's governor in 1967. Journalist Lou Cannon, a biographer of Reagan, said that the future president was keenly aware of the risks of pursuing national office while serving as governor. "Reagan was aware that the charge could become effective if he were an active candidate for the nomination," which is one reason he didn't run until after leaving the governorship, Cannon said.

In 1968, Reagan made some moves to raise his national profile, but he resisted the pull of becoming a "real" candidate. "All the folks around Reagan and his kitchen cabinet assumed he would run for president some day, and win," Cannon said. "Most of them just didn't think this was going to happen in 1968." Reagan eventually ran for president in 1976, then won his second bid in 1980.

Another example of a governor who wasn't hurt by seeing his national profile rise was Bill Clinton, partly because voters in Arkansas enjoyed seeing one of their native sons rise to the top echelons of national politics. In addition, Clinton was something of an institution in the state by the time he ran for president; he had been governor for 10 consecutive years by the time he won the White House in 1992.

"Almost immediately after being sworn in as governor in 1991, Clinton began a 'listening tour' to hear what Arkansans had to say about him considering the 1992 race," said Hendrix College political scientist Jay Barth. "Of course, these 'listeners' said 'go for it.' His 1992 bid was pretty popular in Arkansas. It got the state on the map."

Still, it's more common to see a governor face friction. This usually happens for one of two reasons (or perhaps both): the demands of maintaining a national profile keeps you out of the state, or courting the ideological base of your party puts you at odds with more middle-of-the-road voters back home.

For instance, one of Clinton's successors as governor of Arkansas, Mike Huckabee, lost some support back home when he began toying with presidential ambitions. As governor, Huckabee had been something of a pragmatist, focusing on education, health and infrastructure, said Janine A. Parry, director of the Arkansas Poll. "Once he started actively courting national religious conservatives who play a determining role in Republican presidential primaries, his 'otherness' became problematic for a home-state electorate that was still predominantly Democratic," Parry said.

Another example is Bill Richardson, the governor of New Mexico who ran for president in 2008 while still in office. Even before his presidential bid, Richardson, a former U.S. Ambassador to the United Nations, had demonstrated a desire to play on a broader field, occasionally answering the call to go on diplomatic missions and regularly offering his services as a talking head in the media whenever international crises arose.

While it's hard to separate out other difficulties that hobbled the last year or two of Richardson's tenure -- most notably investigations of alleged corruption in his administration -- Richardson saw a distinct decline in popularity towards the end of his second term. One independent poll in August 2010 had Richardson's approval ratings underwater by a two-to-one margin.

"Gov. Richardson's presidential bid, which was accompanied by numerous out-of-state trips, resulted in rising tensions between himself and many New Mexicans who saw him as either ignoring the state or only pushing policies that benefited his presidential campaign," said one political observer in New Mexico.

Time spent away from the state also hampered Pawlenty's standing in Minnesota. "It became something of a joke at home when he wasn't around, which was kind of always," said one Minnesota Republican. "Every one of his decisions came to be analyzed through the prism of his presidential aspirations."

Among the current crop of governors who have given serious consideration to running for higher office, some have navigated the state vs. national dilemma better than others.

Indiana Gov. Mitch Daniels, a Republican, has maintained high poll numbers during his last year in office, partly because he took himself out of the running for the presidency early on and was dismissive of the notion that he'd be the vice presidential pick.

In Louisiana, Gov. Bobby Jindal, also a Republican, has irritated some political insiders with his national ambitions, but "there is little evidence, beyond snippy reader comments on media web sites, that disillusionment with Jindal among Baton Rouge's political class has spread to actual rank-and-file voters," said one Louisiana political observer. Jindal has been helped by his robust legislative agenda and his political muscle back home, which jibes with a state that is increasingly in tune with him ideologically.

New Jersey Gov. Chris Christie faces a trickier challenge as a Republican who leads a state that tends to vote Democratic in top-of-the-ticket races.

"Christie really pushed hard for a tax cut," said Rutgers University political scientist Cliff Zukin. "Many believe it was so he could go to the Republican Convention and talk about it. It certainly wasn't the 'good government/live within our means' theme he started with when he was elected, and it resulted in some conflict with the Legislature."

Still, Christie's decision not to run for president -- which came despite heavy lobbying by leading figures within the GOP -- seems to have reassured New Jersey voters that he's sufficiently focused on the home front, at least for now.

These days, the risks for any nationally ambitious politician are especially high due to the recession, which has hurt state government budgets hard and has required governors to be especially engaged.

"Voters now expect their governors to put all their efforts into being governor and focusing on stimulating economic recovery, rather than seeking a place on the national political stage," said MacManus of the University of South Florida.