(CNN) Nearly a week after President Donald Trump retweeted anti-Muslim propaganda videos posted by the deputy leader of an ultra-nationalist UK political group, the White House on Tuesday could not -- or chose not -- to say definitively whether he rejected Republican Senate nominee Roy Moore's assertion that Muslims should not be allowed to serve in Congress.

The question was first posed to White House press secretary Sarah Sanders in September, after Moore won the GOP primary in Alabama. It became relevant again, in this setting, when Trump on Monday formally backed Moore ahead of next week's vote.

"Given the President's endorsement," a reporter asked, "does he agree with Roy Moore that Muslims should not be able to serve in Congress?"

Moore in 2006 wrote an article headlined, "Muslim Ellison Should Not Sit in Congress." It compared the decision by Rep. Keith Ellison, D-Minnesota, to be sworn into office with his hand on the Quran to a (hypothetical) new member choosing, in 1943, to "take their oath on Mein Kampf."

"I haven't asked (Trump) about past statements from Roy Moore," Sanders said on Tuesday.

Read More