U.S. Sen. Mark Kirk ducked last week’s Republican National Convention.

The irate, caffeinated Trump Nation partied on without him.

“I can do a lot more for the people of Illinois by staying here rather than running around with a bunch of party operatives,” he said Wednesday at a press conference showcasing his efforts to curb the growing heroin epidemic.

Kirk is the marquee underdog of the 2016 election season, and one of the nation’s most vulnerable GOP senate candidates.

Kirk represents a solidly blue state. Donald J. Trump is at the top of the November ticket. Kirk faces Democratic U.S. Rep. Tammy Duckworth, a well-matched, determined opponent.

On hot-button issues like gun control, inner-city violence, LGBT rights and abortion, he is on the left edge of the GOP.

In June, Kirk doubled down, becoming the first Republican senator to “de-endorse” Trump.
That landed Kirk on Trump’s ever-expanding “dis” list. During a closed-door meeting with Senate Republicans on Capitol Hill, Trump reportedly called the senator “a loser.”

“I don’t think [Trump] has the right temperament, and I felt that he is too racist and too bigoted for the land of Lincoln,” Kirk told me at his downtown office. “I think he’s going to lose Illinois.”

He dumped Trump after the presidential hopeful excoriated U.S. District Judge Gonzalo Curiel, the Mexican-American judge presiding over the Trump University lawsuit.

Trump labeled the judge a “Mexican” and “a hater,” and claimed he could not be impartial in the case.

“For me, obviously I am very sympathetic to the Latino community. Having gone to school in Mexico. And speaking Spanish.” (After graduating from New Trier High School, he attended Universidad Nacional Autónoma de México).

Duckworth “doesn’t speak a word of Spanish,” he noted, and cited a poll his campaign commissioned in March. It “shows that we are leading among Latinos. A lot of that probably is the Abuelitas program.”

In 2005 Kirk launched Abuelitas, Spanish for “grandmother,” in partnership with Mexican social clubs. The effort helps grandmothers in Mexico obtain 30-day travel visas to visit American relatives living in Illinois. More than 2,000 grandmothers have participated, he said.

In Kirk’s poll of 600 likely general election voters, he led Duckworth by nearly 7 percent among Hispanic voters. “Senator Mark Kirk will be re-elected in large part due to voters viewing Kirk differently than other Republicans,” according to the pollster, GS Strategy.

On Friday Crain’s Chicago Business reported that a new poll that shows Kirk “is running strong enough to still have a real shot at hanging on to his U.S. Senate seat.”

The survey, conducted July 11-12 by Basswood Research, puts Kirk ahead, 41.9 percent to 40.4 percent, with a plus or minus 3.5 point margin of error.

Kirk peppered our conversation with Spanish phrases, eager to show off his Español.

He has asked Univision, the Spanish-language TV network, to host a Senate debate. “The Democratic Party says they are the best party to represent Latinos. And the irony of that is that their candidate doesn’t even speak Spanish.”

Duckworth spokesman Matt McGrath responded in an email: “Senator Kirk is attempting to whitewash his record, but the reality is he opposed the DREAM Act and has wavered on comprehensive immigration reform.”

Kirk did not participate in a pre-primary debate co-hosted by Univision, ABC 7 and the League of Women Voters, McGrath added. “It was an excellent event, and provided they partner up again in the fall, we’re planning to be there.”

No puedo esperar. I can’t wait.