It is hard to get a security clearance. You can't do it by yourself, your current or prospective employer has to do this for you. You have to fill out an application. On your way to get security clearance you might have to go threw a poly and interviews where very personal questions are going to be asked.
Yes, possessing a security clearance does not automatically qualify you for TSA PreCheck. You would still need to apply for and pass the TSA PreCheck application process, which includes a background check and an in-person appointment.
It is possible that you could get a security clearance with a DUI. They are mostly looking to see if you are trustworthy, but they also look to see what it would take for someone to leverage you for information, like if you were having an affair, owed a bunch of money, etc. I'd be surprised if you got the job, mostly because driving is probably a core requirement of any job with a security clearance.
Jobs at the Department of Homeland Security can be found at their dedicated "Homeland Security Jobs" page. There one can select from different types and areas (Border Security, Cybersecurity, Economic Security etc.)
Obama does in fact already have a security clearance. Also, past drug use neither precludes one from a security clearance nor from being President -- if it did, several of our former Presidents would have been in trouble.
You would have to apply at a local Social Security Office.
A security template
You go to your nearest social security office and you would be able to apply for it.
The United States Government is one of the top employers of American citizens in the country. Some of the jobs in government are routine and require no special qualifications, but there are other types of jobs where you will be dealing with classified information, state secrets, or have access to restricted areas. Employment in this work requires that a person have a security clearance. The civilian security clearances in the United States Government are Confidential (level 1), Secret (level 2), and Top Secret (level 3). This article deals with employment in the Secret security clearance level.Secret Security EmploymentJust like there are accounting jobs, engineering jobs, aviation jobs and any other type of employment you can think of in the private sector, a person with a Secret security clearance can also hold employment in any of these areas with the United States government. The only difference between the two is that a person with a secret security clearance will be handling information that is not supposed to be seen by anyone other than that person. The information can contain secrets of this country or perhaps access to an area that contains information that is closely guarded. In order to obtain a secret security clearance, a person must already be hired or transferred to the position that requires that clearance. After that, an extensive background check is initiated. If everything checks out, then the secret security clearance is granted.Salary RangesThe salary ranges for someone with a secret security clearance are as large as the number of different types of employment that one can attain with a security clearance. For example, an entry level chemical analyst with a security clearance might start out with a salary of $35,000, but as more experience is gained, the salary increases. This is very similar to what a person without a security clearance would be making. One can argue, however, that the employment with the security clearance might be of more importance because it deals with information that is important to national security.Whatever your passion in life is, you can be sure that having a secret security clearance will not diminish your possibilities of obtaining you dream career. In fact, it can only aid you in finding your perfect job by distinguishing you from others.
In normal scenarios if you are born in the US they would apply for you when you were born, if you are into US by for some work then you have to apply by yourself in the Social Security Office.
The appropriate security classification for an SOP (Standard Operating Procedure) that, if disclosed without authorization, could reasonably be expected to cause damage to national security would be "Confidential." This classification indicates that the information requires protection to prevent harm to national security interests. Access to such documents should be restricted to individuals with the necessary clearance and a need to know.
Change conditions affecting the facility clearance
If it is a matter of spying as it applies to the national security of the US - ordinary criminal law regarding entrapment would not apply.