According to the text, the words their (line 5), their (line 14), which (line 19), who (line 21), and ones (line 26) refer, respectively, to
national nominating conventions, tax returns, public funds, the Revenue Act and presidents.
national political parties, taxpayers, the dollar checkoff, Presidential nominees and candidates.
Taxpayers, taxpayers, The Revenue Act, Presidential nominees and the 1974 Amendments.
national political parties, dollars, the party, public money and candidates.
national nominating conventions, public funds, taxpayers, Revenue Act and Presidential candidates.