Running in a blue state in a presidential year, Brown's personal likability advantage has been viewed as his greatest strength. But the poll shows Brown and Warren with nearly identical favorability numbers. Fifty-three percent of respondents have a favorable opinion of the senator, while 33 percent have an unfavorable view of him. The same amount (53 percent) hold a favorable view of Warren, while 36 percent have an unfavorable opinion of the Democrat. But when asked to choose the more likeable candidate, respondents chose Brown over Warren by a wide margin: 58 percent to 27 percent. With most polls now showing Warren narrowly ahead, Brown has gone on the attack in the last two weeks, releasing two television ads criticizing Warren for listing herself as a Native American at times during her career as an attorney and law school professor. Brown also repeatedly hammered Warren on the issue during the first debate, which was televised statewide earlier this month. The poll shows Brown's attacks have reaped limited rewards. Seventy-one percent of likely voters said the Native American issue will have no impact on their choice in the election, but 24 percent, including 10 percent of Obama supporters, say the controversy has made them less likely to vote for Warren. The poll entered the field the day after the first debate. The Boston Globe poll of 502 likely voters was conducted Sept. 21 through Sept. 27 and carries a margin of error of plus-or-minus 4.4 percentage points. Brown and Warren will meet in their second televised debate Monday night. The debate, which will be held on the campus of U-Mass. Lowell, airs live at 7 p.m. Eastern time on WHDH-TV in Boston, across New England on New England Cable News, and nationwide on C-SPAN.