Yes, but you can both run for your Congressional seat AND run for President. Ron Paul also plans to file for his Congressional seat. Most of the sitting elected officials running for President who aren't term limited are re-filing for their seat.
Nathan, not trying to be mean, but you are just plain wrong on this factually, it's not a matter of opinion. Below is an email from the Colorado official responsible for this. I can send the attachment to you if you like:
Mr. Jansen,
Attached is a candidate packet outlining the filing requirements for U.S. Congress. In order for a candidate to be eligible for this office, they must meet the qualifications for office as well as the filing deadlines. I would also suggest contacting the state political party to ensure that qualifications outlined in the party bylaws are met.
Colorado law does not allow a person to be a candidate for more than one office at a time. I have inserted the statute text below for your review.
Please let me know if I can be of further assistance. Thank you,
Kathryn Mikeworth
Colorado Secretary of State
Elections Division
1700 Broadway, Suite 270
Denver, CO 80290
Phone: 303-894-2200 ext. 6312
1-4-501. Only eligible electors eligible for office.
Statute text
(1) No person except an eligible elector who is at least eighteen years of age, unless another age is required by law, is eligible to hold any office in this state. No person is eligible to be a designee or candidate for office unless that person fully meets the qualifications of that office as stated in the constitution and statutes of this state on or before the date the term of that office begins. The designated election official shall not certify the name of any designee or candidate who fails to swear or affirm under oath that he or she will fully meet the qualifications of the office if elected and who is unable to provide proof that he or she meets any requirements of the office relating to registration, residence, or property ownership. The information found on the person's voter registration record is admissible as prima facie evidence of compliance with this section.
(2)
No person is eligible to be a candidate for more than one office at one time; except that this subsection (2) does not apply to memberships on different special district boards. This subsection (2) shall not prohibit a candidate or elected official of any political subdivision from being a candidate or member of the board of directors of any special district or districts in which he or she is an eligible elector, unless otherwise prohibited by law.
(3) The qualification of any candidate may be challenged by an eligible elector of the political subdivision within five days after the designated election official's statement is issued that certifies the candidate to the ballot. The challenge shall be made by verified petition setting forth the facts alleged concerning the qualification of the candidate and shall be filed in the district court in the county in which the political subdivision is located. The hearing on the qualification of the candidate shall be held in not less than five nor more than ten days after the date the election official's statement is issued that certifies the candidate to the ballot. The court shall hear the testimony and other evidence and, within forty-eight hours after the close of the hearing, determine whether the candidate meets the qualifications for the office for which the candidate has declared. Provisions of section 13-17-101, C.R.S., regarding frivolous, groundless, or vexatious actions shall apply to this section.