Rep. Kevin Cramer (R-N.D.) speaks in Bismarck in 2016. (Charles Rex Arbogast/AP)

Republicans are growing increasingly confident that Rep. Kevin Cramer will run for the Senate, a reversal that could help the GOP in the battle for the majority in the upper chamber of Congress.

In recent days, the North Dakota congressman has shown signs that he is preparing to launch a campaign, according to Republicans familiar with his plans who spoke on the condition of anonymity to describe private deliberations. One senior GOP official said Cramer has been telling people this week that he is running.

But these Republicans were split over whether Cramer would ultimately take the plunge. Some were under the impression that he could announce as soon as this week that he is running. Others were more circumspect, noting that party leaders had been under the impression earlier this year that he was going to run ¡ª only to see him suddenly rule himself out.

¡°We¡¯re just respectfully reconsidering right now. I¡¯ll have a decision by the end of the weekend,¡± Cramer said Tuesday evening. The congressman told the West Fargo Pioneer last week that he was ¡°mildly reconsidering¡± a run for the seat held by Democrat Heidi Heitkamp.

Cramer cited the sweeping GOP tax bill that was passed recently as a factor in his thinking about the Senate run, saying the ¡°enthusiasm for that has grown in the last couple of weeks.¡±

Republicans hold a narrow 51-to-49 Senate majority. The race against Heitkamp is one of their top pickup opportunities. It is one of 10 states Senate Democrats are defending that Donald Trump won in 2016.

The effort to recruit Cramer into the race has not let up since he announced about a month ago that he would not run, Republicans said. There have been concerns among Republicans in Washington about the existing GOP field. Some fear that, without Cramer, the chances of winning back the North Dakota seat would be diminished.

¡°He¡¯s been the number-one target since the beginning,¡± said one of the Republicans familiar with the situation. ¡°That barely paused the day he said he wouldn¡¯t run.¡±

Former North Dakota Republican Party chairman Gary Emineth announced Tuesday that he was ending his Senate campaign, saying that Cramer will run, even though the congressman had made no official announcement.

¡°Given his decision to enter the race, I find myself unwilling to take on a popular incumbent who has done much to endear himself to his constituents,¡± Emineth said in a note to supporters.

State Sen. Tom Campbell (R) is still in the contest. But he is lesser known than Cramer, who has more visibility than most elected officials in North Dakota. He holds the state¡¯s only House seat, giving him more statewide visibility than most other rank-and-file members of Congress.

Cramer is a close ally of President Trump. Trump had tried to persuade Cramer to run, but in early January the congressman said he would not enter the race. According to the senior Republican official, Cramer had told the president at one point that he was going to run.

Democrats moved Tuesday to attack Cramer ahead of a potential announcement. ¡°Anyone who says he¡¯s a top recruit is either lying through their teeth or related to him,¡± said Joshua Karp, a spokesman for American Bridge 21st Century, a Democratic-aligned super PAC.

Cramer said last month that he did not want to ¡°diminish the impact¡± of Trump urging him to run. He said his decision came down to family considerations.

¡°It¡¯s far less intense than flying around the country for the next 10 months every weekend, going to Chicago and New York and, you know, cities far away, to raise adequate funds to, you know, to run,¡± he said on the radio program ¡°What¡¯s On Your Mind?¡±

Robert Costa contributed to this report.