PHOENIX – The four Republicans hoping to be their party's nominee for governor squabbled June 17 over tax policy, vouchers and mail-in voting. But the underlying theme of the hour-long televised debate was each trying to show that he is the only one who can defeat incumbent Democrat Katie Hobbs in November. And that often left Congressman Andy Biggs, who has so far been leading in the polls going into the July 21 primary, on the defensive. kAm%96 3C@256DE 2EE24< 42>6 7C@> 76==@H r@?8C6DD>2?