Presidential candidate Ted Cruz is using Supreme Court decisions to solidify his conservative base (Andrew Harrer/Bloomberg News)

Sen. Ted Cruz (R-Tex.) has proposed a constitutional amendment that would subject Supreme Court justices to periodic judicial elections in the wake of rulings that upheld a key portion of the Affordable Care Act and affirmed gay couples' right to marriage.

“I am proposing an amendment to the U.S. Constitution that would subject each and every justice of the United States Supreme Court to periodic judicial retention elections," Cruz said Saturday, during a speech in Des Moines, Iowa. He also called for such elections in the National Review on Friday.

The proposal from Cruz, who once served as Supreme Court clerk, comes as he is trying to position himself as the presidential candidate of choice for conservatives and evangelicals who disagree with the court's decisions this week. The Texas Republican is using the rulings to paint himself as a stalwart defender of religious freedom, opponent of same-sex marriage and reaffirm his pledge to abolish the Affordable Care Act should he win the presidency.

Cruz is also using the rulings to reemphasize his assertion that he tacks far to the right of the rest of the 2016 GOP field when it comes to social issues, a point he started making in the wake of a controversial religious freedom law Indiana passed in March.

"Sadly we’ve seen several 2016 candidates in response to yesterday’s decision saying it is the law of the land, we must accept it and move on," Cruz said as the Des Moines audience booed. "When Republican candidates are standing up and reciting Barack Obama's talking points things have gone seriously wrong."

Earlier this year Cruz filed legislation that would protect states that prohibit same-sex couples from getting married.

Cruz said last week in Iowa that some Republican presidential candidates chose to "rearrange their sock drawers" in the wake of the Indiana decision. After a backlash to the initial law, Indiana Gov. Mike Pence (R) signed a revised version of the religious freedom bill making it clear that businesses cannot use the legislation as the basis to discriminate based on sexual orientation.

The Texas Republican, who had a tepid start in Iowa, tried to use Saturday's speech, titled "Believe Again" as a way to both solidify his presence in the state and as the uncompromising conservative in the 2016 field. Cruz has come up with a new phrase for the institution he said he is fighting: the "Washington cartel," which he said is comprised by members of both parties, lobbyists, and now Supreme Court justices.

[Read: After a tepid start to presidential run, Ted Cruz plans to ‘play hard’ in Iowa]

"This week's assault was but the latest in a long line of judicial assaults on our Constitution and Judeo-Christian values that have made America great," he said. The Supreme Court "has now forced the disaster of a health-care law called Obamacare on the American people and attempted to redefine an institution that was ordained by God."

Cruz's strategy is to coalesce the support of his conservative base and draw in support from evangelical Christians and conservative libertarians, all but ignoring the Republican establishment and moderates. Cruz said he is the only candidate in the field who is bucking Republican leadership, and said those leaders have been "embarrassed" to stand up for traditional marriage. He said both Democrats and Republicans were "popping Champagne" after the court's rulings because it spared them from having the government "actually follow the law."

The candidate also hit 2012 GOP nominee Mitt Romney, who held a Republican summit earlier this month, for inviting all of the candidates who are "pro-amnesty" on immigration to Utah.