In the case of Laing v. United States, 1975, the Supreme Court ruled on two issues related to tax law. Firstly, it decided that a taxpayer could not be penalized for underpayment in an estimated tax installment if they had overpaid in previous installments within the same year. Secondly, it held that taxpayers who chose to file their returns late were subject to penalties from the date when they should have filed rather than from when they did file. The court reasoned that allowing otherwise would encourage taxpayers to delay filing until after audits or investigations into their taxes were completed.

In the dissenting opinion for Laing v. United States, Justice Blackmun argued that the majority's interpretation of Section 6213(a) was incorrect and overly broad. He contended that this section should not be interpreted to prohibit all assessments before a deficiency notice is mailed but rather only those assessments based on deficiencies. Furthermore, he disagreed with the majority's view that an assessment made after a taxpayer files a petition in Tax Court violates due process rights under the Fifth Amendment. According to him, such an assessment does not deprive taxpayers of property without due process because they still have ample opportunity to challenge it in court before any collection action is taken by IRS. Additionally, he pointed out practical implications of prohibiting immediate assessments which could lead to significant revenue losses for government as delinquent taxpayers might dissipate their assets while litigation is pending.