The Associated Press Rick Perry, the Republican governor of Texas who's likely to soon join the race for the party's presidential nomination, cast his lot and burnished his credentials this weekend with the vastly important base of evangelical Christians and social conservatives. His flashy Houston day of prayer, in which he exhorted Christians to turn to God for answers to the nation's troubles, re-emphasized a vexing US political reality: The battle to win a party's nomination for national office — be it for president or member of Congress — often requires that candidates shun moderation in favor of ideological extremes. And that reality can distort outcomes. Voters can be left with a choice of candidates who ignore the vast American middle ground in favor of the loudest and most driven extremes. While it is impossible to truly know Perry's motives for using the day of prayer as his biggest day in the national spotlight so far, it undoubtedly sealed his credentials among some of the country's most conservative Republican forces — battalions who will flock to state primary elections when the process of selecting a 2012 presidential candidate begins in less than six months. As Perry's light shines bright among many Republican conservatives, he won't be present for premier party events this week in Iowa, where others already in the nominating fight jockey for positive outcomes — a booster rocket for their candidacies fueled by a deeply conservative fervor. The entire field of announced Republican candidates planned to participate in a Thursday debate in Iowa — the first that will include former Utah Gov. Jon Huntsman — and most were staying in the leadoff caucus state for a straw poll two days later when Republican activists cast their presidential preferences for the first time. Perry, since he hasn't announced his candidacy, won't debate in Iowa but plans to deliver speeches to the Alabama Republican party on Friday and to a convention of conservative bloggers in Charleston, South Carolina, on Saturday — the same day as the straw poll. The Texas chief executive's likely run, however, casts a big shadow across Iowa. Perry's main competition — current front-runner and former Massachusetts Gov. Mitt Romney, Minnesota Rep. Michelle Bachmann, and former Minnesota Gov. Tim Pawlenty — are all sharpening their attacks on President Barack Obama. They are assembling their most cutting messages to heap blame on him for the crisis in the US economy. For months, Romney has led the Republican field in polls and money while no less than a half-dozen — Bachmann, Pawlenty and Huntsman among them — have fought to emerge as his main challenger. All the while, the Republican electorate has made clear in polls that it wants more choices, perhaps a conservative who is strong on both economic and social issues. That's where Perry could come in and is what led him to consider a White House bid. Former Alaska Gov. Sarah Palin also is keeping the door open and will be a star attraction at a tea party rally in Iowa on Sept. 3. While many Republicans consider her far less likely than Perry to run, she still has deep support among the small-government, low-tax tea party wing of the party. “He has the potential to appeal to both the economic conservatives and social conservatives,” Iowa Gov. Terry Branstad, a Republican who is unaligned in the race, said of Perry. “The economic conservatives are somewhat up for grabs. I really think it comes down to what does Perry do. I think there is the potential for him to change the race.” Romney, who paid great attention to Iowa in his failed 2008 bid for nomination, returns at midweek for a low key event among supporters as he girds for the inevitable debate attacks on his front-runner status from fellow Republicans. His biggest weakness: He pushed through a Massachusetts health care reform program that is uncomfortably similar to the one Obama shepherded into law nationally. The measure is an anathema to most Republicans who have vowed to repeal the law. Bachmann has risen quickly in national polls and is near the top in Iowa. She has worked in recent weeks to reach Republican voters beyond her tea party base of strong social conservatives. Iowa would be a chance to show broader appeal among Republicans and prove her organization is ready for a national campaign. Pawlenty has worked to build his campaign the past year and a half, but has not caught fire either nationally or in Iowa, the first state south of his home territory of Minnesota. He has spent heavily in Iowa and has campaign workers blanketing the state, which he is counting on the raise his prospects. Neither Romney nor Huntsman, who is bypassing Iowa altogether because of his moderate views don't play well among conservative state activists, will participate in Saturday's straw poll event. Although absent, Perry's chances in the Iowa caucus early next year should he make a run, are seen as good. He's proven, so far, his comfort with the kind of conservatism and evangelical Christian values important to the state's Republican activists. What's more, he brings with him a record of economic and jobs successes in Texas that have confounded most other governors who are fighting to keep their states' heads above water in the long US economic struggle back from the country's most profound downturn in 80 years. As Obama has shifted his policies to appeal to the broad middle ground occupied by most Americans, the challenge for which ever Republican wins the nomination will be to find an elegant way to shift back toward centrist voters — the majority of Americans who typically elect a president. __