Nearly six in 10 Republicans replied with a resounding “don’t know” when asked their opinion of Tim Pawlenty, the former Republican governor of Minnesota who is poised to form a presidential exploratory committee Monday afternoon.

 The broad unfamiliarity among potential GOP voters in the latest Washington Post-ABC News poll is an early challenge for Pawlenty, who will become the first major candidate to formalize his interest in running for the White House.

 Some 28 percent of Republicans and GOP-leaning independents said they have favorable views of Pawlenty, 15 percent unfavorable ones. Most, 58 percent, opted out on the matter.

 In the poll, Pawlenty fares significantly better among Republican men than he does among GOP women. Among GOP men who expressed an opinion, Pawlenty runs about 4 to 1 favorable, but among women, there’s a narrow six-point gap between the percentages expressing favorable and unfavorable views (19 to 13 percent, with 67 undecided). Forty-eight percent of Republican men expressed no opinion.

A late February NBC-WSJ poll had President Obama thumping Pawlenty in a hypothetical 2012 match-up, 50 to 31 percent. In that poll, the president was up by 22 -points among political independents.

How much of Obama’s advantage in that poll had to do with the public’s not knowing much about Pawlenty, a two-term governor, will start to clarify after Monday’s announcement.