WASHINGTON — In a victory for advocates of campaign finance transparency, the Supreme Court refused on Tuesday to block a trial judge’s ruling that required some nonprofit groups that place political advertisements to disclose the names of their contributors.

The Supreme Court’s brief order gave no reasons and did not note any dissenting votes. The order vacated an earlier one entered on Saturday by Chief Justice John G. Roberts Jr. that temporarily blocked the ruling.

That ruling, issued last month by Judge Beryl A. Howell of the Federal District Court in Washington, required many nonprofit groups that placed advertisements supporting or opposing political candidates to disclose the identities of donors who had contributed more than $200. Before the ruling, such groups could generally shield their donors from public scrutiny.

The case was brought by Citizens for Responsibility and Ethics in Washington, or CREW, a watchdog group. It sued the Federal Election Commission and Crossroads GPS, a conservative group. Judge Howell struck down a federal regulation that had effectively allowed secret contributions, saying it conflicted with a federal statute.