Ronald Reagan struggled to return his campaign to economic themes today, but his own comments on the hostage issue got in the way again.

"I believe that this [Carter] administration's foreign policy helped create the entire situation that made their kidnap possible," Reagan told reporters when he left his hotel in Louisville, Ky., this morning. "And I think the fact that they've been there that long is a humiliation and disgrace to this country."

At the airport in Orlando, Fla., where he was campaigning today, President Carter said the hostages are too important for him to comment on publicly and he accused Reagan of breaking a pledge not to inject the subject of the hotages into the presidential campaign. However, the hostage issue has been raised in recent weeks by administration officials who suggested to reporters that the Americans were about to be released.

"The fate of the hostages is too important to be made a political football," the president said when asked about Reagan's statement today.

Reagan was asked repeatedly throughout a day of campaigning in this border state region what he would do differently than Carter to free the American hostages, who today completed their 352nd day of captivity in Iran.

Over and over again, Reagan declined to say what he would do.

Carter said that on Sept. 13, Reagan had pledged not to make the negotiations over the hostages a partisan issue in the campaign. "I regret that he has broken this pledge, but I am not going to depart from the prior commitment we have made to continue to do everything we could to preserve the lives and safety of the hostages and to see them brought back at the earliest possible moment."

Asked if he had a response to Reagan's charge that the administration's foreign policy weakness had led to the hostage crisis, Carter shook his head, said, "No," and walked away.

Campaigning in Kansas City tonight, Reagan responded: "I don't think I've broken that pledge. The hostages have been a matter of discussion and of all your questions for quite some time now. I would think that breaking such a pledge might be if I waited until 7:15 on Election Day and then brought the subject up, as he [Carter] did in the Wisconsin primary."

In Louisville this morning, the Republican nominee said it wasn't wise for a president to do his "negotiating in the press," as Reagan said Carter had done. When Reagan was asked in this southern Illinois coal-mining town whether he had a plan of his own to free the hostages, he replied: "There's just no way I could answer that question without giving something away."

Reagan's criticism of Carter for mishandling the hostage issue surfaced at a Louisville rally Monday night. The remark was designed to put Carter on the defensive on the "war-peace issue" and also to take the edge off any political benefit the White House might receive from an election-eve attempt to bring the hostages home.

Today, Reagan tried to get back on the economic issue, which his own and other polls show to be Carter's most vulnerable issue. In Herrin, which Carter carried four years ago but where Reagan is now believed to be ahead, the GOP nominee made a hard-hitting and well-received speech deploring the policies of the Environmental Protection Agency, which he said make it difficult for coal producers to market the region's high-sulfur coal.

"Coal mines have closed down in southern Illinois, yet we have imported 16 million tons of foreign coal," Reagan said. "You are faced with the absurd situation that while you have so much coal right under your feet, you must export your jobs somewhere else."

But when Reagan took an extensive stroll of the town's main street, both the reporters accompanying him and several of the local voters seemed to have foreign policy on their minds.

Reagan continued to say, as he has the last few days, that he is a man of peace who would be less likely than Carter to lead the nation into war.

"I'm convinced that the greatest risk of war comes from the kinds of foreign policy we have today under this administration where our friends don't know whether they can trust us . . . [and] our adversaries certainly don't respect us," Reagan told a clothing store owner who said he was a veteran of World War II.

Reagan and his aides took some comfort, as foreign policy ccontinued to dominate the presidential campaign, from the anticipated endorsement Wednesday from former Minnesota senator Eugene McCarthy, the 1968 antiwar candidate.

"This, maybe, will give some people confidence that I don't eat my young," Reagan said in Herrin.

Reagan lost the contact lens in his right eye today and misread several lines of his speech to a large crowd assembled in front of the Herrin City Hall. The crowd gasped when the GOP nominee mispronounced the name of the community he was in as "Heroine."

But Reagan recovered and had the crowd applauding him when he denounced federal energy policies, and mocked a campaign boast of Carter's in which the president says: "We're well on the way to recovery. I think we'll have a good Christmas."

"Well, maybe it will be a good Christmas in the White House, but he better not look into the windows of too many homes around America," Reagan said. "Is it going to be a good Christmas for the thousands of steelworkers who were tossed into unemployment lines by the Carter economic policies . . . . And what kind of Christmas will it be for so many Americans who find the price of nearly everything flying out of sight?"

Reagan plans to make the economy the subject of a half-hour paid television speech that will be aired over CBS at 10:30 p.m. Friday.