<P> A bill of attainder is a law by which a person is immediately convicted without trial . An ex post facto law is a law which applies retroactively, punishing someone for an act that was only made criminal after it was done . The ex post facto clause does not apply to civil matters . </P> <P> Section Nine reiterates the provision from Section Two that direct taxes must be apportioned by state populations . This clause was also explicitly shielded from constitutional amendment prior to 1808 by Article V. In 1913, the 16th Amendment exempted all income taxes from this clause . This overcame the ruling in Pollock v. Farmers' Loan & Trust Co. that the income tax could only be applied to regular income and could not be applied to dividends and capital gains . Furthermore, no tax may be imposed on exports from any state . Congress may not, by revenue or commerce legislation, give preference to ports of one state over those of another; neither may it require ships from one state to pay duties in another . All funds belonging to the Treasury may not be withdrawn except according to law . Modern practice is that Congress annually passes a number of appropriations bills authorizing the expenditure of public money . The Constitution requires that a regular statement of such expenditures be published . </P> <P> The Title of Nobility Clause prohibits Congress from granting any title of nobility . In addition, it specifies that no civil officer may accept, without the consent of Congress, any gift, payment, office or title from a foreign ruler or state . Emoluments were a profound concern of the Founders . However, a U.S. citizen may receive foreign office before or after their period of public service . </P> <P> No State shall enter into any Treaty, Alliance, or Confederation; grant Letters of Marque and Reprisal; coin Money; emit Bills of Credit; make any Thing but gold and silver Coin a Tender in Payment of Debts; pass any Bill of Attainder, ex post facto Law, or Law impairing the Obligation of Contracts, or grant any Title of Nobility . </P>

Why is the first article of the constitution important