Wisconsin Gov. Scott Walker (R) remains locked a tight re-election campaign, according to a new poll released Wednesday.

The Marquette Law School poll of those likeliest to vote this fall shows Democratic nominee Mary Burke leading Walker 49 percent to 47 percent, an advantage that is within the survey's margin of error.

The poll affirms what strategists in both parties have anticipated for months: this is going to be a competitive fall campaign. In the July survey, Walker and Burke were running about even.

A former executive at the bicycle company Trek and an ex-state commerce secretary, Burke is running a campaign focused on Walker's record on jobs and the economy. Walker has been tying Burke to unpopular former governor Jim Doyle (D), under whom she served as commerce secretary.

The Marquette poll of 609 likely voters was conducted from Aug. 21-24. It has a margin of error of plus or minus 4.1 percentage points.