Washington (CNN) Former South Carolina Gov. Mark Sanford, who announced this weekend that he will launch a longshot primary bid for the 2020 Republican nomination, argued Monday that the growing field of Republicans challenging President Donald Trump strengthens their anti-Trump message.

"I think it strengthens it. What the administration is basically said -- what the Trump campaign has said is: it was just Bill Weld for a while, it's a voice crying in the wilderness, it's -- pay it no attention. All of a sudden, when you end up with three candidates and three different candidates saying there's something wrong with this presidency, what's going on here is not consistent with the Republican Party that we know about, believe in and invested major portions of our life in, that's a different conversation," Sanford told CNN's John Berman on "New Day."

On Sunday, Sanford joined two other Republicans -- former Massachusetts Gov. Bill Weld and former Illinois Rep. Joe Walsh -- in challenging Trump for the GOP presidential nomination. While more than 20 Democrats are vying for the chance to take on the President in the general election, Sanford argued that the Republican Party needs to take an introspective look at itself because it has lost its way on "a couple different fronts."

Sanford identified a number of those areas during his CNN appearance on Monday, saying he thinks his party is "not having a conversation on debt, deficit and government spending, which used to be a cornerstone to what the Republican Party was about." He also said Republicans need to place more attention on the "institutions, the framework of government" and have a conversation about "humility and tone in the office, which I think this president misses."

Asked by Berman if he's trying to damage Trump in the general election should he be the party's nominee again, Sanford said: "No. I don't own what I don't own," adding that "at the end of the day, the American way is competition ... and that should be the case for the Republican Party as well."

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