As he drives along the flat, rain-slick Route 31 toward this small midstate city, Chip Ryan, 26, a field representative for the Republican National Committee, describes the political newcomer he's trying to help.

"His name's Jim Butcher. He's 45, an attorney, straight-laced, very religious, very involved in civic affairs, charities, athletics, that sort of thing. Very sincere.

"In other words, he's credible. We don't have just a warm body. We've got a commodity. We've got a real live candidate."

Jim Butcher, running for the Indiana State, is one of the great hopes of the national GOP this year even though most people, even in his own state, have never heard of him.

He is one of hundreds of candidates for local legislatures across the country that the Republican National Committee has targeted for extra money and support.

In a quiet, little-noticed drive, the GOP is spending $2 million of its $6 million campaign budget to regain at least a quarter of the 800 state legislative seats it has lost to Democrats since 1972.

"It's the highest priority we have - our largest single expenditure," says the party's national chairman, Bill Brock. "Our goal is to get control of enough statehouses in the next two elections so that we can influence the way boundaries are drawn for state legislative and congressional districts."

To Brock and other national GOP officers, the drive is a matter of survival. For in most states the people elected to legislatures this year and in 1980 are and will be the ones who will draw the legislative boundaries in 1981 and 1982 to reflect population shifts as recorded in the 1980 census.

"The last census cost us about 40 seats in Congress," Brock says. "We just cannot afford that again."

Usually, when the party in control of a legislature draws lines, the other party accuses it of gerrymandering - that is, of setting the boundaries so that the opposition's minority status is perpetuated.

"We're gerrymandered so badly that in the last general election we got 42 percent of the vote but only 33 percent of the seats in the House of Representatives," laments Charles R. Black, the GOP's national political director.

The Republicans have not had control of the House since 1953. The party has not had a net gain in state legislatures since 1966, although it has picked up some 30 seats in special elections during the last year.

This year the GOP has control of both houses in state legislatures only in Colorado, Wyoming, Idaho and South Dakota. It dominates one house in eight other states - Maine, Vermont, New York, Kansas, Indiana, North Dakota, Arizona and New Hampshire - or nine if you include Nebraska, which is technically nonpartisan but really Republican.

Of some 7,500 state legislative seats in the nation, Republicans hold about 2,400. "We want to pick up a leat 200 this time and 400 in 1980 in states where it counts in terms of redistricting," Brock said.

Among the main targets are New York, Michigan, Tennessee, Kansas, Vermont, Florida, Illinois - and Indiana.

"The national effort is particularly significant here," said Indiana State Republican Chairman Bruce B. Melchert. "We have no major state or national races to overshadow the legislative races, and I think we have a good chance of keeping control of our house and gaining control of the senate."

The Indiana House has 52 Republicans and 48 Democrats. Its Senate has 28 Democrats and 22 Republicans. This year all House members and half of the senators are being elected; 17 of the 25 incumbent senators running are Democrats.

"We're trying to pick off the ones we think are vulnerable," said Chip Ryan, one of 16 field representatives that the national GOP has dispatched throughout the country on its "Project Survival."

"When your opponent gets less than 55 percent of the vote, he's vulnerable," Ryan said. Jim Butcher's Democratic opponent, state Sen. Merton Stanly, got 51 percent in 1974, and his district is about 53 percent Republican.

"Most of these local campaigns are ill-conceived and poorly executed," Ryan said. "They're lost, not won. Typically, a candidate gets together with his brother-in-law and cousin, and they spend four Sundays discussing the color of his brochure and how many emery boards and matchbooks to order for the campaign.

"Luckily, we got to Jim Butcher before that could happen."

One day last week Ryan, Butcher, and Butcher's campaign manager, Cye Zwirn, reviewed the candidate's progress here.

"Stanley has put out an article indicating that I'd be nothing but a rubber stamp for (Republican) Gov. (Otis) Bowen," Butcher said. "I'd like to respond."

Well, you could get out a press release calling it a bum rap, and you'd end up on the obit page," Ryan replied. "Remember what I told you: keep to your own plan. You've got to get on Page One.

"Why don't you propose a one-time, 25 percent cut in the state income tax? You've got to drop a bomb on Stanley - make his teeth rattle."

Ryan then reviewed Butcher's campaign budget - $16,000, which included $3,000 from the national committee, $2,500 from the state committee and $1,300 from the state Senate's Republican Campaign Committee.

"You got three grand left," Ryan noted. "I'd like to beef up the radio advertising."

"I've got 600 spots," Butcher said. "That's five or six times what Stanley's got."

"That's okay. You can't lose from too much media. When is your lit drop?"

"You know your literature. You've got to flood the community. Monday night before the election I want you to flush the headquarters - get out all the brochures, the letters, anything that creeps and crawls."

"We've got 1,000 yard signs," Butcher said. "When should we get them out?"

"Wait till after Halloween," Ryan advised. "If you do it before then, the little ruffians will take them down. Besides, you want to make a big splash with them all at once."

Butcher said he would soon be speaking at a high school class, and Ryan suggested he use the occasion to announce that if elected he would start an intern program so high school students could learn about state government.

"That's excellent," said Zwirn. "But wouldn't we be giving the competition a new idea?"

"There are no new ideas in politics," Ryan said.

Stanley, a conservative Democrat who is 60 and has been in public office 26 years, said that since there are no real issues in the campaign, he is "concerned that Butcher is spending a barrel of money on name-recognition advertising.

"I'll probably spend less than $5,000." He said, "The Senate campaign committee gave me $3,000, but I didn't get one cent from the state or national Democratic committees. They said they had no money.

"I'll increase my radio ads somewhat, but I'm simply not going to buy a Senate seat by spending a ton of money."

Stanley and Butcher agree that the main - if largely unspoken - issue is redistricting after the 1980 census. Indiana has 11 congressional seats, eight of them held by Democrats and three by Republicans.

"If the Republicans get control of both houses, they can put three Democrats into one district in the southern part of the state and at least two into one district in the east," Stanley said.