Breakout performances on the stump in Iowa early this year vaulted Mr. Walker, who is expected to officially enter the presidential race next month, into the lead in polls in the state with the nation’s first nominating contest, and cemented him among the top three Republican contenders in most national surveys.
But the expectations created by that early prominence, as well as a growing threat from conservative firebrands like Senator Ted Cruz, have taken a toll. To protect his lead in Iowa, a state with a heavily conservative Republican electorate, Mr. Walker has taken a harder line on a number of issues than his allies had anticipated.
Now a growing number of party leaders say Mr. Walker is raising questions about his authenticity and may be jeopardizing his prospects in states where voters’ sensibilities are more moderate.
