Mercer added that Trump's selection of Governor Pence, who has "long been a stalwart supporter of the unborn," as his vice president was assuredly a positive sign for pro-lifers.
He pointed to Pence's acceptance speech where the governor insisted that "for the sake of the sanctity of life...we must ensure that the next president appointing justices to the Supreme Court is Donald Trump."
Other pro-lifers acknowledged concerns about Trump's history on pro-life issues and controversial remarks he has made about women.
However, they added, his promise to nominate conservative judges to the Supreme Court combined with his selection of Pence as a running mate sets Trump apart from the presumptive nominee of the Democratic Party, Hillary Clinton, as the choice for pro-lifers.
Ultimately, "to me it's about the Supreme Court," Kansas Governor Sam Brownback told CNA on Wednesday.
"My confidence [in Trump] has been growing," Marjorie Dannenfelser, president of the pro-life group Susan B. Anthony List, told CNA. "And it started at a very small place."
"You couldn't find a man of better integrity, authenticity," she said of Mike Pence, adding that Trump has picked some solid pro-life staff members like policy director Josh Mashburn and pollster Kellyanne Conway.
Christian also praised the vice-presidential candidate, saying that many Republicans' criticisms of Pence have been "a bit unfair."
Despite Trump's choice of Pence as a running mate, however, Christian is not sold on Trump's commitment to the pro-life cause.
"As someone who is both Catholic and a pro-life activist, I'm seeing little to no enthusiasm for Donald Trump," Christian stated to CNA, noting Trump's "past positions on abortion," and the a campaign that has largely steered clear of the life issue.
"His past positions on abortion and clear lack of interest in the subject, which seems to be reflected in how little the issue has come up at the Convention, is making it difficult for even single issue voters to trust that he is the real deal," Christian said.
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While he criticized the Republican Party for taking "pro-life voters for granted" and failing to advance the pro-life cause beyond speeches, this year's campaign has said little about the pro-life stance at all. "[The] reality is that very little has even been said to encourage those strongly motivated by their pro-life convictions," he continued.
"Given this and the Democratic platform's extreme position on abortion, I've never seen so many pro-lifers distraught over their choices for the presidency," Christian lamented.
He added that, as a Catholic, he is also concerned by other issues highlighted – or largely ignored– by the Trump campaign and the speeches at the RNC Convention.
In addition, he criticized the party's failure to address what he called "a marriage crisis" among working- class families, including the economic hurdles that face many couples.
"It is a serious, grave threat to the common good," Christian told CNA. "Vague platitudes about the importance of the family are not enough. It has not been an encouraging week for serious pro-family voters."
Religious freedom is another issue where Christian was concerned both about Trump's proposed policies and the convention's rhetoric. He called out Trump's proposed ban on Muslim immigrants as "a stunning attack on religious freedom," and explained that the move was particularly concerning when the Catholic Church and other organizations "may be facing showdowns over people and organizations having to abort children or stop their work - life and death issues."