海角大神

A razor-close race for the Wisconsin governorship is drawing national attention and money 鈥� and on Tuesday, it鈥檚 luring President Obama into the fray.

At issue, as Mr. Obama jets into Milwaukee for a campaign rally, is whether Democrats can unseat Gov. Scott Walker and deliver a symbolic thumping to tea-party-style politics in the nation鈥檚 heartland.

A victory by Democrat challenger听Mary Burke could also effectively end Governor Walker鈥檚 presidential aspirations as the 2016 White House race comes into view. A track record leading a state can be a great stepping stone to the Oval Office, after all, but the jump gets a lot harder when one has听been voted out of office.

Walker has long been considered the leader in this race. But an average of recent polls shows him up by only 0.2 percentage points against Ms. Burke, .

That edge is essentially no edge at all.

What can Obama deliver, given that he鈥檚 weighted down by high 鈥渦nfavorable鈥� ratings among Americans generally? Maybe some help mobilizing stalwart Democratic voters, including African Americans. The calculation is that this trumps the risk that his presence could hurt at the margins among more moderate voters who are on the fence.

In the current campaign, many US Senate candidates in tight races have been distancing themselves from Obama, and it鈥檚 the gubernatorial candidates, like Burke, who have welcomed him to their podiums.

Tuesday鈥檚 event is a dinner-hour rally at a Milwaukee school.

Walker is known for cutting taxes and 鈥� notoriously in the view of many Democrats 鈥� curbing the collective-bargaining rights of public sector labor unions.

Although tax cuts aren鈥檛 generally an election-losing issue, the ad wars in the campaign center heavily on dueling perceptions of Walker鈥檚 economic record. The state has lower-than-average unemployment, but has lagged behind others in the Midwest in the pace of job creation and behind Walker鈥檚 own stated goal on that front.

Burke touts her record in a former executive at Trek Bicycle Corp. and her seat on the school board in Madison as signals that she鈥檒l manage the state鈥檚 economy well and out-invest Walker on education.

Walker was elected in 2010, the same year the tea party movement rose to national prominence as a force in Republican politics, and he鈥檚 admired by many in that movement. He鈥檚 been positioning himself as a staunch conservative ahead of a possible run for president in 2016.

If he wins this governor鈥檚 race, he would emerge as one of the main contenders in view, alongside other current and former governors, such as Chris Christie of New Jersey (who鈥檚 scheduled to campaign for Walker soon) and Jeb Bush of Florida.

If he loses, his presidential chances fade and Democrats听and their labor allies, still reeling from losing a high-profile recall vote against Walker in 2012,听will rejoice in winning a referendum on union-bashing and other right-wing economic and social policies. (Ads attacking Walker also have focused on his record opposing abortion.)