New Hampshire Sen. Robert C. Smith yesterday abandoned his independent campaign for the presidency, paving the way for his return to the Republican Party and a likely claim to succeed the late Sen. John H. Chafee (R-R.I) as chairman of the Senate Environment and Public Works Committee.

But Smith did not back off his scorching criticism of the GOP when he left it three months ago, and several Republicans, still bristling at his criticism, said he may have some "explaining" to do before the party rewards him with a powerful chairmanship.

If his seniority as a Republican is not challenged, Smith would have an edge over Sen. James M. Inhofe (R-Okla.), who ranks directly behind Smith in tenure on the panel. Both are staunch conservatives with low ratings from environmental groups, presenting a sharp contrast with Chafee's strong pro-environment record.

Environmentalists regard Smith only slightly more favorably than Inhofe: "apocalypse soon as opposed to apocalypse now," said Daniel J. Weiss, political director for the Sierra Club.

Smith said he was abandoning his candidacy because he could not raise enough money to finance it, although he said he drew "tens of thousands" in small contributions indicating a "broad base of support . . . for my conservative agenda."

He said he would not discuss his political plans until after the Saturday funeral of Chafee, who died last Sunday. But he acknowledged he has talked with party leaders, including Senate Majority Leader Trent Lott (R-Miss.) and Republican National Chairman Jim Nicholson, about returning to the GOP fold. He emphasized that the talks took place well before Chafee died.

Smith, who was trailing badly in a bid for the Republican presidential nomination, left the party in July with a blistering speech to the Senate in which he accused the GOP of abandoning its "core values" in pursuit of power. "The Republican platform is a meaningless document that has been put out there so suckers like me and maybe suckers like you out there can read it . . . I did not come here to compromise my values to promote the interests of a political party," he said. He would "stay an independent, whatever happens in the future," he added.

Since leaving the party, Smith has continued to vote for Republican positions and attend party caucuses and fund-raisers. In a statement yesterday, Nicholson said he has come to "respect him [Smith] greatly" and has "assured him that if he were to return to our party, he would be welcome."

Senators rarely if ever depart from seniority in selecting chairmen, although the decision is up to the committee Republicans and the whole GOP caucus. One source said the chairmanship will probably go to Smith if he returns to the party and no one challenges his credentials.