Republicans on Monday blocked Democrats’ attempt to obtain President Trump’s tax returns.

House Republicans won a procedural vote, 229-185, that called for his IRS returns. The Wall Street Journal reported that all Democrats were in favor of the release.

“If there’s nothing there, then what are Republicans afraid of?” Rep. Nancy Pelosi, D-Calif., said. She reportedly said Republicans “made themselves accomplices” to Trump in hiding his financial affairs.

Trump’s refusal to disclose his tax returns is a break with presidential tradition. He has said he would be happy to release them after the completion of an IRS audit.

Two weeks ago, House Republicans blocked an attempt by Democrats to use an obscure law to obtain the tax returns from the IRS. Democrats on the House Ways and Means Committee tried to frame the issue as a matter of national security, questioning whether Trump has any investments in Russia.

U.S. Sen. Susan Collins, a Republican, said last week that she is open to using a subpoena to investigate President Donald Trump’s tax returns for potential connections to Russia.

Collins, a Republican who has served as a U.S. senator from Maine since 1997, sits on the Senate Intelligence Committee, which is investigating Russian interference in the 2016 election.

Collins was asked if the committee would subpoena Trump, who’s also a Republican. She said she hopes for “voluntary cooperation” but is open to using a subpoena if necessary.

“This is a counter-intelligence operation in many ways. That’s what our committee specializes in,” she said during the radio appearance. “We are used to probing in depth in this area.”

Trump has said he has no investments in Russia, and Democrats acknowledged they have no evidence otherwise. They said that is one reason they want to obtain access to Trump's returns.

The Associated Press contributed to this report