Clinton plans to deliver a voting rights speech Thursday. (AP Photo/Richard Shiro, File)

Democratic presidential candidate Hillary Rodham Clinton plans to call for an early voting period of at least 20 days in every state.

Clinton will call for that standard in remarks Thursday in Texas about voting rights, her campaign said. She will also criticize what her campaign calls deliberate restrictions on voting in several states, including Texas.

The former secretary of state's address at historically-black Texas Southern University in Houston comes as Democrats pursue legal challenges to voting rule changes approved by Republican legislatures in several states.

Clinton and her allies claim the changes are aimed at narrowing the electorate in ways that benefit Republicans.

“This is, I think, a moment when we should be expanding the franchise,” Clinton campaign chairman John Podesta said in an interview. “What we see in state after state is this effort by conservatives to restrict the right to vote.”

The legal effort began late last month with lawsuits in Wisconsin and Ohio, both presidential battleground states.

“This lawsuit concerns the most fundamental of rights guaranteed citizens in our representative democracy — the right to vote,” lawyers wrote in a federal complaint filed Friday in Wisconsin.

The challenge to a cutback in early voting in Wisconsin was filed by lawyers including Democratic election lawyer Marc Elias, who is the Clinton campaign’s top lawyer. Elias was not acting on behalf of the campaign, although all Democrats including Clinton could benefit if early voting were expanded.

“That right has been under attack in Wisconsin since Republicans gained control of the governor’s office and both houses of the State legislature in the 2010 election,” the lawsuit alleges.