With midterm elections less than two months away, Christian conservatives are enlisting churches in eight battleground states to register voters, gather crowds for rallies and distribute voters’ guides comparing the candidates’ stands on issues that conservatives consider “family values.”

This election year, however, the religious conservatives are facing resistance from newly invigorated religious liberals and moderates who are creating their own voters’ guides and are organizing events designed to challenge the conservatives’ definition of “values.”

Both religious flanks are looking nervously over their shoulders at the Internal Revenue Service, which this year announced a renewed effort to enforce laws that limit churches and charities from involvement in partisan political campaigns.

“We became concerned in the 2004 election cycle that we were seeing more political activity among charities, including churches,” said Lois G. Lerner, the director for exempt organizations at the I.R.S. “In fact, of the organizations we looked at, we saw a very high percentage of some improper political activity, and that is really why we have ramped up the program in 2006.”

The I.R.S. issued a report in February that said nearly half of the 110 tax-exempt organizations it investigated after the 2004 elections for improper political activity were churches. Of the 40 churches that the I.R.S. had finished investigating, 37 were found to have violated the law. These churches were given warnings or penalized with excise taxes and, although none lost their tax exemptions, the I.R.S. is still investigating seven more cases against churches.

Capitalizing on the crackdown, the advocacy group Americans United for Separation of Church and State plans to begin mailing letters today to 117,000 clergy members in 11 states warning them to avoid “any activity designed to influence the outcome of a partisan election,” by either supporting or opposing a particular candidate.

“The stakes for these churches are higher than ever before because of the I.R.S.’s new enforcement efforts,” said the Rev. Barry W. Lynn, executive director of Americans United for Separation of Church and State. “The I.R.S. is taking this very seriously, and I think it’s because the situation was spinning out of control.”

Mr. Lynn said that conservative churches in 2004 had constructed a political machine he likened to “a church-based Tammany Hall.” He said he expected their voters’ guides to be skewed to favor Republican candidates. “It’s absolutely illegal, it’s wrong and it divides churches,” he said.

But a leader of Focus on the Family, a conservative Christian organization whose affiliates are distributing voters’ guides in eight states, said its guides would be nonpartisan and comply with I.R.S. rules.

Tom Minnery, senior vice president for government and public policy at Focus on the Family, said, “What I see are people from the left complaining when people from the right decide they want to be citizens.”

Focus on the Family, a ministry founded by James W. Dobson and based in Colorado Springs, has stepped into the vacuum left by the Christian Coalition, which pioneered the voters’ guide tactic in churches in the 1990’s under the leadership of Ralph Reed, but is now in disarray in many states.

Focus on the Family’s state affiliates plan to register voters and distribute voters’ guides in churches this year in Pennsylvania, Maryland, Michigan, Ohio, New Jersey, Minnesota, Montana and Tennessee: all states where Republican candidates favored by religious conservatives are on the ballot.

“Obviously, they’re battleground states,” Mr. Minnery said. “Our overall desire is for our constituency, generally conservative church people, to be involved citizens.”

He said he regarded the threat of I.R.S. penalties as exaggerated, and he called Mr. Lynn of Americans United “the bully on the playground.” He said the Alliance Defense Fund, a legal advocacy group, had offered to “defend for free any pastors if they’re challenged” by the I.R.S.

Focus on the Family and its affiliates are holding pre-election rallies in Pittsburgh, St. Paul and Nashville, but no candidates will be invited to speak. The group also plans to send letters, Mr. Minnery said, “laying out the issues that separate the candidates in certain major races,” but he refused to say which races.

Many of the most visible groups representing religious moderates and liberals are distributing materials that do not mention the candidates.

The voters’ guides distributed by two such groups — Sojourners, a predominantly evangelical organization founded by Jim Wallis, and Catholics in Alliance for the Common Good — will enumerate principles that they say religious voters should use to evaluate candidates.

Among the principles are a commitment to reducing poverty and preserving the environment and caring for immigrants: in short, the left’s version of “family values.”

“We’re not doing candidates,” Mr. Wallis said. He added: “The principle comes from Martin Luther King Jr., who never endorsed a candidate, not once. He made them endorse his agenda. We want to create an agenda with a social movement behind it that holds politicians accountable.”

Catholics United for the Common Good, which is affiliated with the Catholics in Alliance group, is compiling “candidate evaluations” for many of the senate races, using 25 criteria important to Catholic voters, said Chris Korzen, the group’s director. But they do not plan to distribute paper copies, only to post it on the Web.

“It’s a matter of resources,” he said.