Election '84: five crucial races for the US Senate

Massachusetts Republicans have given the state's voters a clear-cut ideological choice for US senator Nov. 6 - and perhaps cost the national GOP a chance for a very satisfying upset.

They nominated ultraconservative millionaire industrialist Raymond Shamie for the Senate seat being vacated by liberal Democrat Paul E. Tsongas. Democrats, in the state's September primary, chose liberal Lt. Gov. John F. Kerry to run against Mr. Shamie. Many observers, including some national Republican leaders, felt that moderate Elliot L. Richardson, would have been more likely to defeat the Democrats and give Massachusetts its first statewide GOP victory in 12 years. But Mr. Shamie beat Mr. Richardson handily in the primary.

Shamie, who in his first Senate bid two years ago was soundly defeated by Democratic Sen. Edward M. Kennedy, is running on Ronald Reagan's coattails. Those coattails this year are much longer in Massachusetts than any conservative Republican's would ordinarily be - that is, Reagan is leading Walter Mondale.

Shamie campaign hopes that stronger and more visible ties between the Senate candidate and the President could be built by at least one joint appearance in the state apparently will be fulfilled. A last-minute Reagan campaign decision is due to bring the President to Massachusetts later this week to help Shamie. A Reagan TV commercial, strongly urging Bay Staters to vote for Shamie, has been widely broadcast.

Recent disclosures that 10 years ago the GOP senatorial nominee was briefly a member of the far right John Birch Society could, in the opinion of some observers, make it more difficult for him to attract nonconservative voters. This despite his attempt to disassociate himself from the controversial group and some of its positions, which he terms ''too extreme.'' Mr. Kerry first gained national prominence in the early 1970s as leader of Vietnam Veterans Against the War. Particularly helpful to him is the nearly 4-to-1 voter registration edge Democrats hold over Republicans in Massachusetts. But slightly more than one-third of the total electorate is independent, and Shamie is directing a lot of his campaign at those voters.

Growing conservativism among Bay State Democrats, especially those concerned about issues like abortion and school busing and others impressed by the economic recovery, works in Shamie's favor. These voters helped a conservative Democrat, Edward J. King, take the party's nomination, and ultimately the governorship, away from Michael S. Dukakis in 1978. Some of Mr. King's political cohorts are supporting Shamie, although the former governor himself has stayed out of the senatorial campaign.

Most of the state's better known Republicans, including Mr. Richardson, are backing Shamie with varying degrees of intensity. Kerry has solid support from leading Democrats, including Gov. Michael S. Dukakis and US House Speaker Thomas P. O'Neill Jr.

Both candidates are wealthy, and it shows: Shamie had put $935,979 of his own money into his campaign through September; Kerry had either contributed or lent

Last of six pages on regional contests in the Nov. 6 election. Previous pages appeared Sept. 6 and 20, Oct. 11, 23, and 26.