Amid an increasingly nasty political campaign, Sen. Luther Strange's approval rating is just under 45 percent, according to Morning Consult's new Senator Approval Rankings.

The rankings are based on more than 140,000 interviews with registered voters nationwide conducted from April 1 through June 18. The rankings for Alabama lawmakers comes from state responses. Full methodology is available here.

Forty-four percent said they approve of the job Strange is doing as compared to 30 percent and 26 percent who said they had no opinion.

Alabama's former Attorney General, Strange was appointed to the job by ex-governor Robert Bentley in February. The controversial appointment came after Strange asked a House committee investigating Bentley to stop its work while his office conducted what he described as "related work."

Bentley resigned in April as part of plea deal related to campaign finance and ethics violations in connection to his relationship with former aid Rebekah Caldwell Mason.

Strange faces Rep. Mo Brook, former Alabama Chief Justice Roy Moore and a host of other Republicans in the Aug. 15 special election primary.

Alabama's senior Senator, Richard Shelby, has an approval rating of 53 percent compared to a disapproval rating of 29 percent. Eighteen percent said they had no opinion of the Republican Senator.

Strange's approval rating was the 11th lowest in the Senate; Shelby's was the 40th highest.

According to Morning Consult's survey, the 10 most popular Senators among their constituents are: