Complex sentence: Reagan pulled his support for the ERA shortly before announcing his 1976 candidacy for President; the 1976 Republican National Convention renewed the party's support for the amendment, but in 1980, the party qualified its 40-year support for ERA.
Split into simpler sentences: Reagan pulled his support for the ERA shortly before announcing his 1976 candidacy for President. The 1976 Republican National Convention renewed the party's support for the amendment, but in 1980 the party qualified its 40-year support for ERA.