Rep. Vito Fossella went on trial Friday on the drunken-driving charges that exposed an extramarital relationship, sidetracked a promising political career and could lead to time in jail.

Fossella, the lone Republican in Congress from New York City, was arrested just after midnight on May 1 in suburban Virginia. He had spent the previous morning at the White House celebrating the New York Giants' Super Bowl victory.

"There was a strong odor of alcoholic beverage coming from the car and his lips were stained red," police officer Jamie Gernatt testified in Alexandria General District Court. The police officer said Fossella told him he'd had two or three glasses of wine.

The non-jury trial was expected to take a day. Police say his blood-alcohol level was 0.17 percent, and under state law anyone convicted of having a BAC above 0.15 must serve a mandatory five-day jail term.

He could avoid immediate incarceration by appealing the verdict to a higher court.

Three lawyers sat at the defense table with Fossella as he listened glumly but intently to the officer's testimony. At one point, he looked incredulous as the officer described one of their conversations on the night of the arrest, but otherwise he showed little reaction to Gernatt's description.

Defense lawyer Jerry Phillips challenged the types of field sobriety tests given to Fossella, and the accuracy of the Intoxilyzer 5000 machine that was used later to measure his blood alcohol content.

"What we have is a stop that doesn't indicate any impairment," argued Phillips.

At one point, Phillips had the officer step down from the witness chair and take one of the sobriety tests himself — standing on one leg for 30 seconds.

When Phillips suggested the congressman might have wobbled a bit because he was nervous about being pulled over for running a red light, Gernatt replied: "I completed the test and I'm pretty nervous right now."

Police said the married 43-year-old told them he was headed to see his sick daughter. Given that his wife and children live in New York, that statement set off alarms and eventually led to the revelation he had secretly fathered a daughter, now 3 years old, with a Virginia woman named Laura Fay, a former Air Force officer and congressional liaison.

After admitting the relationship, Fossella announced he would not seek re-election, a drastic fall for a politician once viewed as a potential mayor of New York City. His downfall has also created an opportunity for Democrats to gain a seat in Congress in November.

Fossella's troubles have only further hurt his state party's election chances next month. If a Democrat wins Fossella's seat, it will mark the first time in 35 years that all of New York City has been represented by Democrats.

"We're full speed ahead," said Pollack.

The lawyer is challenging the accuracy of the blood-alcohol content tests administered to Fossella. Police say his blood-alcohol level was 0.17 percent, and under state law anyone convicted of having a BAC above 0.15 must serve a mandatory five-day jail term.

Even if he is convicted Friday, he would not go to jail right away, since a defendant still has the right to appeal such a verdict to a higher court.

By coincidence, Fossella's trial comes as another member of Congress, powerful Alaska Sen. Ted Stevens, is on trial in Washington on charges he did not report gifts of expensive home renovations.

Fossella's troubles have only further hurt his state party's election chances next month. If a Democrat wins Fossella's seat, it will mark the first time in 35 years that all of New York City has been represented by Democrats.